Healthy Diet Archives - Health Tips From The Professor

Can A Healthy Diet Help You Lose Weight?

December 30, 2025 by Dr. Steve Chaney

What’s New About This Study?

Author: Dr. Stephen Chaney

New Year’s resolutions are just around the corner. Some of you will resolve to lose weight, and some of you will resolve to eat healthier. But can you do both?

Any restrictive diet will give you short-term weight loss. And weight loss will give you improvement in blood parameters that might signal a reduced risk of heart disease, stroke, and diabetes.

The operative word here is “might”. Long-term studies are required to determine whether a diet actually reduces the risk of chronic diseases.

So, the important question becomes, “Can weight loss diets be healthy long term”. For some of them, the answer is a clear no. Others are unlikely to be healthy but have not been studied long term, so we don’t know whether they are healthy or not.

That’s the dilemma most of you face this January. If most weight loss diets are unhealthy long term, do you have to choose between weight loss and good health when you make your New Year’s resolutions?

Maybe not. What if you started from the opposite perspective? What if you asked, “Can a healthy diet help you lose weight?” The study (S Schutte et al, American Journal of Clinical Nutrition, 115: 1-18, 2022)) I will review this week suggests it can.

How Was This Study Done?

This was a randomized controlled trial, the gold standard of clinical studies. The investigators recruited 100 healthy, abdominally obese men and women aged 40-70. At the time of entry into the study none of the participants:

Had diabetes.
Smoked
Had a diagnosed medical condition.
Were on a medication that interfered with blood sugar control.
Were on a vegetarian diet.

The participants were randomly assigned to:

A high-nutrient quality diet that restricted calories by 25%.
A low-nutrient-quality diet that restricted calories by 25%.
A continuation of their habitual diet.

The study lasted 12 weeks. The participants met with a dietitian on a weekly basis. The dietitian gave them all the foods they needed for the next week and monitored their adherence to their assigned diet. They were advised not to change their exercise regimen during the study.

At the beginning and end of the study the participants were weighed, and cholesterol, triglycerides, and blood pressure were measured.

Can A Healthy Diet Help You Lose Weight?

This study compared a healthy diet to an unhealthy diet with the same degree of caloric restriction. And it compared both diets to the habitual diet of people in that area. This study was performed in the Netherlands, so both weight loss diets were compared to the habitual Dutch diet.

To put this study into context, these were not healthy and unhealthy diets in the traditional sense.

Both were whole food diets.
Both included fruits, vegetables, low-fat dairy, and lean meats.
Both restricted calories by 25%.

The diets were designed so that the “high-nutrient quality” diet had significantly more plant protein (in the form of soy protein), fiber, healthy fats (monounsaturated and omega-3 fats), and significantly less added sugars than the “low-nutrient-quality” diet.

When the investigators measured weight loss at the end of 12 weeks:

Participants lost significant weight on both calorie-restricted diets compared to the group that continued to eat their habitual diet.

- That is not surprising. Any diet that successfully restricts calories will result in weight loss.

Participants on the high-nutrient quality diet lost 33% more weight than participants on the low-nutrient-quality diet (18.5 pounds compared to 13.9 pounds).

Participants on the high-nutrient quality diet lost 50% more inches in waist circumference than participants on the low-nutrient-quality diet (1.8 inches compared to 1.2 inches).

- Waist circumference is a direct measure of abdominal obesity.

When the investigators measured blood pressure, fasting total cholesterol levels, and triglyceride levels at 12 weeks:

Prescription for good health overhead with stethoscope, healthy fresh food and exercise equipment, with copy space.

These cardiovascular risk factors were significantly improved on both diets.

- Again, this would be expected. Any diet that causes weight loss results in an improvement in these parameters.

However, the reduction in total serum cholesterol was 2.5-fold greater in the high-nutrient quality diet group than in the low-nutrient-quality diet group.

The reduction in triglycerides was 2-fold greater in the high-nutrient quality diet group than in the low-nutrient-quality diet group.

The reduction in systolic blood pressure was 2-fold greater and the reduction in diastolic blood pressure was 1.67-fold greater in the high-nutrient quality diet group than in the low-nutrient-quality diet group.

The authors concluded, “Our results demonstrate that the nutrient composition of an energy-restricted diet is of great importance for improvements of metabolic health in an overweight, middle-aged population. A high-nutrient quality energy-restricted diet enriched with soy protein, fiber, monounsaturated fats, omega-3 fats, and reduced in fructose and other added sugars provided additional health benefits over a low-nutrient quality energy-restricted diet, resulting in greater weight loss…and promoting an antiatherogenic blood lipid profile.”

In short, participants in this study lost more weight and had a better improvement in risk factors for heart disease on a high-nutrient-quality diet than on a low-nutrient-quality diet. Put another way, a healthy diet can help you lose weight. Healthy eating helped them lose more weight and gave them greater improvement in their health.

What’s New About This Study?

Simply put this study confirms that:

Caloric restriction leads to weight loss, and…

Weight loss leads to improvement in cardiovascular risk factors like total cholesterol, triglycerides, and blood pressure.

- This is not new. It is true for any diet that results in caloric restriction.

However, this study breaks new ground in that it shows a high-nutrient quality diet results in significantly better…

Weight loss and…

Reduction in cardiovascular risk factors….

…compared to a low-nutrient quality diet with the same degree of caloric restriction.

What Does This Study Mean For You?

As I said above, the distinction between a “high-nutrient-quality” diet and a “low-nutrient-quality” diet may not be what you might have expected.

Both diets were whole food diets. Neither diet allowed sodas, sweets, and highly processed foods.

Both included fruits, vegetables, grains, and lean meats.

Both reduced caloric intake by 25%.

- If you want to get the most out of your weight loss diet, this is a good place to start.

However, in this study the investigators designed their “high-nutrient-quality” diet so that it contained:

More plant protein in the form of soy protein.

- In this study they did not reduce the amount of animal protein in the “high-nutrient-quality” diet. They simply added soy protein foods to the diet. I would recommend substituting soy protein for some of the animal protein in your diet.

More fiber.

- The additional fiber came from substituting whole grain breads and brown rice for refined grain breads and white rice, adding soy protein foods, and adding an additional serving of fruit.

More healthy fats (monounsaturated and omega-3 fats) in place of saturated fats.

- The additional omega-3s came from adding a fish oil capsule providing 700mg of EPA and DHA.

Less added sugar.

All these changes make great sense if you are trying to lose weight.

I would group these changes into 7 recommendations.

1) Follow a whole food diet. Avoid sodas, sweets, and highly processed foods.

2) Include all 5 food groups in your weight loss diet. Fruits, vegetables, whole grains, dairy, and lean proteins all play an important role in your long-term health.

3) Eat a primarily plant-based diet. My recommendation is to substitute plant proteins for at least half of your high-fat animal proteins. And this study reminds us that soy protein foods are a convenient and effective way to achieve this goal.

4) Eat a diet high in natural fiber. Including fruits, vegetables, whole grains, beans, nuts, seeds, and soy foods in your diet is the best way to achieve this goal.

5) Substitute healthy fats (monounsaturated and omega-3 fats) for unhealthy fats (saturated and trans fats) in your diet. And this study reminds us that it is hard to get enough omega-3s in your diet without an omega-3 supplement.

6) Reduce the amount of added sugar in your diet. This is best achieved by eliminating sodas, sweets, and highly processed foods from the diet.

7) Finally, I would like to remind you of the obvious. No diet, no matter how healthy, will help you lose weight unless you cut back on calories. Fad diets achieve that by restricting the foods you can eat or the time you are allowed to eat. In the case of a healthy diet, the best way to do it is to cut back on portion sizes and choose foods with low caloric density.

The Bottom Line

A recent study asked, “Can a healthy diet help you lose weight?” This study was a randomized controlled study, the gold standard of clinical studies. The participants were randomly assigned to:

A high-nutrient quality diet that restricted calories by 25%.
A low-nutrient-quality diet that restricted calories by 25%.
Continue with their habitual diet.

These were not healthy and unhealthy diets in the traditional sense.

Both were whole food diets.
Both included fruits, vegetables, low-fat dairy, and lean meats.
Both restricted calories by 25%.

The diets were designed so that the “high-nutrient quality” diet had significantly more plant protein (in the form of soy protein), fiber, healthy fats (monounsaturated and omega-3 fats), and significantly less fructose and other added sugars than the “low-nutrient-quality” diet.

At the end of 12 weeks:

Participants on the high-nutrient quality diet lost 33% more weight and had better cardiovascular markers than participants on the low-nutrient-quality diet.

For more details on this study, what this study means for you, and my 7 recommendations for a healthy weight loss diet, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease.

_____________________________________________________________________________

My posts and “Health Tips From the Professor” articles carefully avoid claims about any brand of supplement or manufacturer of supplements. However, I am often asked by representatives of supplement companies if they can share them with their customers.

My answer is, “Yes, as long as you share only the article without any additions or alterations. In particular, you should avoid adding any mention of your company or your company’s products. If you were to do that, you could be making what the FTC and FDA consider a “misleading health claim” that could result in legal action against you and the company you represent.

For more detail about FTC regulations for health claims, see this link.

https://www.ftc.gov/business-guidance/resources/health-products-compliance-guidance

_______________________________________________________________________

About The Author

Dr. Chaney won numerous teaching awards at UNC, including the Academy of Educators “Excellence in Teaching Lifetime Achievement Award”.

Dr Chaney also ran an active cancer research program at UNC and published over 100 scientific articles and reviews in peer-reviewed scientific journals. In addition, he authored two chapters on nutrition in one of the leading biochemistry text books for medical students.

Since retiring from the University of North Carolina, he has been writing a weekly health blog called “Health Tips From the Professor”. He has also written two best-selling books, “Slaying the Food Myths” and “Slaying the Supplement Myths”. And most recently he has created an online lifestyle change course, “Create Your Personal Health Zone”. For more information visit https://chaneyhealth.com.

For the past 45 years Dr. Chaney and his wife Suzanne have been helping people improve their health holistically through a combination of good diet, exercise, weight control and appropriate supplementation.

How To Live To 117

December 9, 2025 by Dr. Steve Chaney

The Secrets To A Long And Healthy Life

Author: Dr. Stephen Chaney

Today’s “Health Tip” is a bit unusual. It’s not based on a clinical study with thousands of participants. It’s not even a clinical study based on dozens of people. It’s a case study of one individual.

The study was published in Cell Reports Medicine, but I learned about it in our local newspaper (Yes, the professor still reads the newspaper in addition to published clinical studies. I don’t rely on the internet for all my information.)

I chose this case study because it was so interesting. It is based on the life of a woman, Maria Branyas Morera, who lived in good health to the age of 117. In her later years she asked her physician, Dr. Manel Estellar – chair of genetics at University of Barcelona’s School of Medicine, to study her and see if he could find out why she lived so long.

The results were fascinating. And while it could be argued that the data from a single individual may be misleading, the conclusions from her doctor’s investigation were consistent with the results of the much larger “Blue Zone” study of centenarians living in regions where a high percentage of people lived to 100 and beyond. I will talk about that study below.

How To Live To 117

Maria Branyas was born in San Francisco in 1907 of Spanish immigrant parents. Her father died when she was 8 and her mother moved back to Spain to be with her family. She married and had a son who died at age 52 and two daughters who are now 92 and 94.

Part of the reason for her longevity was that she took good care of herself:

She followed a Mediterranean diet.

She did not smoke or drink.

She walked an hour every day until her 90s. Eventually she had to cut back because of physical limitations but remained as active as possible. When walking became difficult she entered a nursing home.

She kept mentally active. For example, she played the piano every day until she was 112.

Part of the reason was socioeconomic.

She and her family lived in the same town.

She had a close circle of friends and family for emotional support.

And as her friends died, she made new ones.

- This is something that is often not discussed in the aging literature. As you age and your friends die off, it is easy to become isolated, which increases the likelihood of depression and death. The decision to make new friends in your latter years is a choice.

And part of the reason was genetic.

In the words of her doctor, “She won the genetic lottery with respect to genetic variants that protect against risk factors like high cholesterol, dementia, heart disease, and cancer.”

- However, we need to remember that genetics is not everything. Other members of her immediate family shared the same genetic traits, yet died prematurely from Alzheimer’s, cancer, tuberculosis, and heart disease.

- I like to say, “Genetics loads the gun. Lifestyle pulls the trigger”. In short, both contribute to longevity.

The final part of the puzzle goes beyond genetics.

She had an immune system that was unusually strong for someone her age and inflammation that was unusually low for someone her age. Those were probably due to:

- Epigenetic modifications to her DNA that are associated with younger individuals.

- - Quick review: Epigenetic modifications affect gene activity and are controlled by diet, lifestyle, and the environment.

- - We can never know exactly what caused her youthful epigenetics, but she did have a very healthy diet and lifestyle.

- She had a microbiome associated with low inflammation.

- - Quick Review: The term microbiome refers to all the microorganisms in our gut and elsewhere on our body. Our microbiome is strongly affected by what we eat and other lifestyle factors such as body weight.

- - In her case, one example of her anti-inflammatory microbiome was a high abundance of Bifidobacteria, probably a direct result of the three yogurts she ate each day.

The Secrets To A Long And Healthy Life

This brings me to the “Blue Zone” study. I have talked about it in a previous issue of “Health Tips From The Professor”. Let me give you the short version here.

Dan Buettner is a journalist who was fascinated by the topic of longevity. He identified five regions from around the world where an unusually high percentage of people lived into their 100s. He then put together a team of top scientists in the fields of demographics, social anthropology and statistics to study the characteristics of centenarians in each of these regions and got National Geographic to fund the study.

You can see his book on the left, and I will summarize the main conclusions of his study below. Of course, the most important question is how the information garnered from Maria Branyas compares with the conclusions of the “Blue Zone” study. I will indicate that below.

#1: They engage in moderate intensity exercise every day. The answer for Maria is a clear, “Yes”.

#2: They stop eating before they are full. We don’t know this for sure, but she did appear to be at ideal weight towards the end of her life.

#3: They eat a mostly plant-based diet. She ate a Mediterranean diet which qualifies.

#4: They have a libation with their meals. For Maria, this is a “No”.

#5: They have a purpose in their life. We have no information on this aspect of Maria’s life.

#6: They set aside time for relaxation with friends and family. Clearly, this was important for Maria. As old friends died off, she searched for new ones.

#7: They participate in a spiritual community. We have no information on this aspect of Maria’s life.

#8: They put family first. Clearly, family was very important to Maria.

#9: They surround themselves with communities that share their values. It also appears that this was important to Maria.

In short, in his study of Maria’s secrets to longevity Dr. Esteller approached the question of longevity from a different perspective than Dan Buettner. It is regrettable that he didn’t use the data accrued by the “Blue Zone” study as a starting point for his study. But it is clear that Maria epitomized many of the longevity characteristics identified in the “Blue Zone” study.

And, of course, Dr. Esteller’s expertise is human genetics, and he added important information about the importance of genetics, epigenetics, and our microbiome in influencing longevity.

The Bottom Line

The world’s oldest human recently died at age 117. Before she died, gave her doctor permission to study her and determine how she was able to live so long. In short, she asked her doctor to use her life to understand how to help other people live a long and healthy life.

That study has recently been published. The results showed:

Her lifestyle mirrored many of the lifestyle characteristics that were associated with longevity in the previous “Blue Zone” study of centenarians (people living to 100 and beyond).

This study also identified genetic, epigenetic, and microbiome factors associated with longevity

For more details about the study, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

_____________________________________________________________________________

For more detail about FTC regulations for health claims, see this link.

https://www.ftc.gov/business-guidance/resources/health-products-compliance-guidance

________________________________________________________________________

About The Author

Dr. Chaney won numerous teaching awards at UNC, including the Academy of Educators “Excellence in Teaching Lifetime Achievement Award”.

For the past 53 years Dr. Chaney and his wife Suzanne have been helping people improve their health holistically through a combination of good diet, exercise, weight control and appropriate supplementation.

What Diet Is Best For Healthy Aging?

October 28, 2025 by Dr. Steve Chaney

What About Primarily Meat-Based Diets?

Author: Dr. Stephen Chaney

It’s so confusing. Everyone claims they have clinical proof that their diet is the best. You will be healthier and live longer.

But the diets are so different. They range from vegan to keto. They can’t all be equally healthy. What is the truth?

To answer that question, we first need to understand how the proponents of each diet can claim theirs is the perfect diet for health and longevity. It’s because they base their claims on:

Short-term studies. Most of their claims are based on studies that range from a few weeks to a few months. You need 20- or 30-year studies to measure the effects of a particular diet on health outcomes.

Biological markers (Things like cholesterol and triglyceride levels, blood sugar control, and/or inflammation). Biological markers can predict possible health outcomes. But without long-term studies on actual health outcomes, you don’t know whether those predictions are accurate.

Comparisons with the typical American diet. Any diet looks good compared with the American diet.

Elimination of highly processed foods. While these diets emphasize different foods, they are all whole food diets. Again, any diet that eliminates processed foods is an improvement.

- It doesn’t matter whether you restrict calories, restrict certain foods or food groups, or restrict the time you allow yourself to eat. You unconsciously eat less.

- And when you eat less, you lose weight.

- And when you lose weight, your cholesterol and triglyceride levels fall, your blood sugar control improves, and inflammation decreases.

- That’s why short-term weight loss and improvement in biological markers are virtually identical with vegan and keto diets. Those diets are as different as any two diets could be. But they are both highly restrictive diets.

The take-home lesson is clear. Don’t be confused by claims based on short-term studies. What you should look for is:

Long-term studies (20 years or more)…

that look at the effect of diet on health outcomes, and…

do not compare their diet with the typical American diet.

When I first reviewed this topic 8 years ago, I could only find a few studies that met these criteria:

One study showed that people consuming primarily plant-based diets weighed less than people who consumed primarily meat-based diets for 20 years or more.

Other studies showed that people consuming primarily plant-based diets had a reduced risk of diabetes and heart disease compared to people consuming primarily meat-based diets for 20 years or more.

These are valuable observations, but they are limited. That’s why I was so excited when I came across a recent 30-year study (A-J Tessier et al, Nature Medicine, volume 31, pages 1644-1652, 2025) looking at the effect of 9 different diets on longevity and health outcomes. In short, this study looked at the effect of different diets on healthy aging.

How Was This Study Done?

The authors of this study used data from 105,015 participants in the Nurses’ Health Study (NHS) and Health Professionals Follow Up Study (HPFS). Both studies enrolled participants in 1986 and followed them through 2016. In short, they were both 30-year studies. Participants with preexisting chronic diseases were excluded from the study.

Lifestyle factors and medical histories were assessed every two years.

A detailed dietary assessment was conducted every four years. The assessments measured the intake of 152 foods. Food intakes were averaged over the duration of the study for each participant.

[Note: This study did not measure how the diets of participants changed between 1986 and 2016, although that is an interesting question. Perhaps a future study is planned.]

Based on the foods eaten, the diets of the participants were evaluated for adherence to 9 dietary patterns, which I have described in more detail below.

[Note: To be clear, the participants were not trying to follow these diets. They ate what they ate, and the investigators subsequently compared their dietary pattern with various healthy diets.]

For each of the diets included in this study, participants were divided into quintiles based on how closely their food intake adhered to the recommendations for that diet. Then the highest quintile was compared to the lowest quintile to determine how well that diet predicted “healthy aging” after a 30-year follow-up.

The term “healthy aging” was based on 5 criteria:

Longevity – achieving an age of 70 or more.

Absence of the top 11 major chronic diseases (cancer, diabetes, myocardial infarction (heart attack), coronary artery disease, congestive heart failure, stroke, Parkinson’s disease, multiple sclerosis, and ALS).

No impairment of cognitive function.

No impairment of physical health.

No mental health issues.

In other words, these were not just individuals who survived 70 years or more. They survived and thrived. They were enjoying their golden years because they still had good health and excellent quality of life.

Diets Included In This Study

The diets included in this study were:

AHEI – Alternative Healthy Eating Index (A scoring system developed by Harvard researchers to measure overall diet quality based on its ability to predict lower risks of heart attacks, strokes, and diabetes).

aMed – Alternative Mediterranean Diet Index (The aMed diet index differs from the original Med index by separating fruits and nuts into different groups, eliminating dairy, emphasizing whole grains, and excluding red and processed meats in favor of chicken and fish).

DASH – Dietary Approaches to Stop Hypertension (The name speaks for itself. But I also sometimes refer to this diet as “the Americanized version of the Mediterranean diet’ because it features foods more familiar to Americans. For example, it allows more red meat options than most of the other diets in this list.

MIND – Mediterranean-Dash intervention for Neurogenerative Delay (It is a dietary pattern designed to reduce the risk of Alzheimer’s disease and other forms of dementia. It combines elements of the Mediterranean and DASH diets but differs from both by emphasizing berries as a major fruit source, among other things.)

hPDI – Healthy Plant-Based Diet Index (It is a scoring system that measures adherence to a diet rich in healthy plant-based foods and lower consumption of less-healthy plant foods and animal foods.)

PHDI – Planetary Health Diet Index (It emphasizes foods (primarily plant foods) that are healthy and are good for the environment. Of the diets on this list, it is the most restrictive and closest to a vegan diet)

EDIH – Empirical Dietary Index For Hyperinsulinemia (It is a scoring system that measures the potential of a diet to cause chronically high insulin levels, which is associated with type 2 diabetes and certain cancers.)

EDIP – Empirical Dietary Inflammation Pattern (It is a scoring system that measures the inflammatory potential of a diet.)

UPF – Consumption of Ultraprocessed Foods (Since recent studies have shown that most Americans get between 55 and 70% of their calories from ultraprocessed foods, this is fast becoming a measure of the typical American diet.)

Note: Except for the UPF diet, these are all whole food, primarily plant-based diets.

What Diet Is Best For Healthy Aging?

Here are the results of the study (drum roll, please):

Of the 105,015 participants in this study, only 9.3% achieved healthy aging.

Adherence to any of the 8 healthy diets improved the probability of achieving healthy aging.

The odds of achieving healthy aging ranged from 1.45 for the Healthy Plant-Based Diet to 1.86 for the Alternative Healthy Eating Index.

If you were to pick one winner, it would be the Alternative Healthy Eating Index. And if you were to define healthy aging as achieving an age of 75 or more with the other 4 criteria, the odds increase to 2.24 (more than double) for the Alternative Healthy Eating Index.

As you might expect, adherence to a diet high in ultraprocessed foods had the opposite effect. It decreased the odds of achieving healthy aging by 32%.

When you look at each of the criteria for healthy aging individually, the results were a bit more nuanced:

For survival to 70+ years, the Alternative Healthy Eating Index and the Planetary Health Diet Index were tied. Both increased the odds of survival by more than 2-fold.

The Alternative Healthy Eating Index and the Planetary Health Diet Index were also tied for surviving to 70 with intake cognitive health and intact physical function.

The Empirical Dietary Index For Hyperinsulinemia edged out the Alternative Healthy Eating Index for freedom from 11 chronic diseases.

The effect of healthy diets on the odds of achieving healthy aging is independent from BMI, smoking, and physical activity. This means that:

The effects of healthy diets on healthy aging were not because people consuming healthy diets weighed less, smoked less, or exercised more.

Even if some of your lifestyle choices are suboptimal, choosing a healthy diet will increase your odds of surviving and thriving.

Finally, the study looked at the effects of individual foods on healthy aging. The results were:

Higher intakes of fruits, vegetables, whole grains, unsaturated fats, nuts, legumes, and low-fat dairy products increase your odds of healthy aging.

Higher intakes of trans fats, sodium, sugary beverages, and red or processed meats decrease your odds of achieving healthy aging.

The effects of these foods on healthy aging aren’t novel. They are consistent with dozens of other studies that have looked at the effect of individual foods on long-term health outcomes. In fact, the diets included in this study were chosen because they included foods that positively affect health outcomes and minimize foods that negatively affect health outcomes.

What About Primarily Meat-Based Diets?

I have good friends who advocate for primarily meat-based diets such as keto, paleo, and carnivore. I’m sure they are going to say, “This study is a sham. It only included primarily plant-based diets, so, of course, it is only going to show benefits for primarily plant-based diets.” I can hear their their questions now:

Why didn’t this study include any of the primarily meat-based diets? My answer is: “All the popular meat-based diets exclude one or more of the food groups associated with health and longevity and emphasize one or more of the food groups associated with a shorter, less healthy life. And these food associations are consistent among multiple long-term studies looking at the effect of various foods on health outcomes.

The authors could have constructed a similar index for each of the popular meat-based diets. But they would have been the inverse of the plant-based diet indices because the foods included and excluded from plant-based and meat-based diets are opposite. Therefore, just like the UPF index, they would have been associated with a decreased probability of achieving healthy aging.”

Why did the scientists designing this study ignore the proven health benefits of primarily meat-based diets? My answer is: “The “proven benefits” of primarily meat-based diets are based on short-term studies showing the effects of those diets on biological markers. Long-term studies looking at health outcomes are lacking.”

But modern primarily meat-based diets are a special case because they limit carbohydrates and cause ketosis. Why weren’t they included in the study? My answer is: “The Atkins diet limits carbohydrates and causes ketosis. It has been around for more than 50 years. And, to my knowledge, there are no studies showing it is beneficial long term. If the Atkins diet cannot be shown to have long-term health benefits, it is unlikely that modern diets that mimic it are healthy long term.

What Does This Study Mean For You?

The answer is clear. If you want to survive and thrive in your 70s and beyond, choose a whole food, primarily plant-based diet.

If you want the absolute best diet, follow the Alternative Healthy Eating Index recommendations. There are many online resources to guide you.

However, any whole food, primarily plant-based diet will do. The ones with the most online resources are the Mediterranean, DASH, and MIND diets. Choose the one that best fits your food preferences and lifestyle.

If you want to go more vegetarian, the Healthy Plant-Based Diet is a bit easier than a strict vegan diet.

If you are concerned about the environment, the Planetary Diet is best for you.

If you have specific health issues like hypertension, diabetes, or inflammation, there are diets designed just for you.

And if following structured diets is not your style, just:

Eat more fruits, vegetables, whole grains, unsaturated fats, nuts, legumes, and low-fat dairy products.

Eat less trans fats, sodium, sugary beverages, and red or processed meats, and ultraprocessed foods.

Finally, even if some of your lifestyle choices are suboptimal, this study shows choosing a healthy diet will increase your odds of surviving to your 70s and thriving.

The Bottom Line

A recent 30-year study looked at the effect of 8 whole food, primarily plant-based diets on healthy aging defined as:

Achieving an age of 70 or more.

The absence of the top 11 major chronic diseases.

No impairment of cognitive function.

No impairment of physical health.

No mental health issues.

The key findings were:

Adherence to any of 8 whole food, primarily plant-based diets improved the probability of achieving healthy aging.

The odds of achieving healthy aging ranged from 1.45 for the Healthy Plant-Based Diet to 1.86 for the Alternative Healthy Eating Index.

For more information on this study, why primarily meat-based diets were not considered healthy enough to be included in this study, and what this study means for you, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

____________________________________________________________________________

For more detail about FTC regulations for health claims, see this link.

https://www.ftc.gov/business-guidance/resources/health-products-compliance-guidance

_______________________________________________________________________

About The Author

Dr. Chaney has a BS in Chemistry from Duke University and a PhD in Biochemistry from UCLA. He is Professor Emeritus from the University of North Carolina where he taught biochemistry and nutrition to medical and dental students for 40 years. Dr. Chaney won numerous teaching awards at UNC, including the Academy of Educators “Excellence in Teaching Lifetime Achievement Award”. Dr Chaney also ran an active cancer research program at UNC and published over 100 scientific articles and reviews in peer-reviewed scientific journals. In addition, he authored two chapters on nutrition in one of the leading Biochemistry textbooks for medical students.

The Low Carb Myth

September 23, 2025 by Dr. Steve Chaney

The “Goldilocks Effect”

Author: Dr. Stephen Chaney

The low carb wars rage on. Low carb enthusiasts claim that low-carb diets are healthy. And they claim the lower you go, the healthier you will be. Let me start with some definitions:

The typical American diet is high carb. It gets about 55% of its calories from carbohydrates. [Note: The Mediterranean and DASH diets also get about 55% of their calories from carbohydrates. I’ll talk more about that later.]

Moderate carb diets get 26-46% of their calories from carbohydrates. Examples include the low carb Mediterranean diet and the Paleo, South Beach, and Zone diets.

Low carb diets get <26% of their calories from carbohydrates. The Atkins diet is the classic example of a low carb diet.

Very low carb diets get <10% of their calories from carbohydrates. Examples are the Keto and Carnivore diets.

And I don’t need to tell you that the Keto and Carnivore diets are receiving a lot of favorable press lately.

But some health experts warn that low carb and very low carb diets may be dangerous. For example, several studies have reported that low carb diets increase the risk of mortality (shorten lifespan).

As a consumer you are probably confused by the conflicting claims. Are low carb diets healthy, or is this another myth? In this issue of “Health Tips From the Professor” I am going to discuss two very large studies that came to opposite conclusions.

Both were what we call meta-analysis studies. Simply put, that means they combine the data from several smaller studies to obtain more statistically reliable data. But as Mark Twain said, “There are lies. There are damn lies. And then there are statistics.”

The first study, called the Prospective Urban Rural Epidemiology (PURE) study, was published a few years ago. It included data from 135,335 participants from 18 countries across 5 continents. That’s a very large study, and normally we expect very large studies to be accurate.

It showed a linear relationship between carbohydrate intake and mortality. Simply put, the more carbohydrate people consumed, the greater their risk of premature death. The results from the PURE study had low carb enthusiasts doing a victory lap and claiming it was time to rewrite nutritional guidelines to favor low carb diets.

Whenever controversies like this arise, reputable scientists are motivated to take another look at the question. They understand that all studies have their weaknesses and biases. So, they look at previous studies very carefully and try to design a study that eliminates the weaknesses and biases of those studies. Their goal is to design a stronger study that reconciles the differences between the previous studies.

And this study had two glaring weaknesses.

The percent carbohydrate intake ranged from 40% to 80%. It showed that a moderate carbohydrate intake might be healthier than a high carbohydrate intake, but it provided no information about low carb or very low carb diets.

The data was primarily from Asian countries. It was not clear whether it was relevant to the kind of diets consumed in North America and Europe.

A second study published a year later (SB Seidelmann et al, The Lancet, doi.org/10.1016/S2468-2667(18)30135-X) eliminated these weaknesses and resolved the conflicting data.

How Was The Second Study Done?

This study was performed in two parts. This first part drew on data from the Atherosclerosis Risk in Communities (ARIC) study. That study enrolled 15,428 men and women, aged 45-64, from four US communities between 1987 and 1989. This group was followed for an average of 25 years, during which time 6283 people died.

Carbohydrate intake was calculated based on food frequency questionnaires administered when participants enrolled in the study and again 6 years later. The study evaluated the association between carbohydrate intake and mortality.

The second part was a meta-analysis that combined the data from the ARIC study with all major clinical studies since 2007 that measured carbohydrate intake and mortality and lasted 5 years or more. The total number of participants included in this meta-analysis was 432,179, and it included data from previous studies that claimed low carbohydrate intake was associated with decreased mortality.

The Low Carb Myth

The results from the ARIC study were:

The relationship between mortality and carbohydrate intake was a U-shaped curve.

- The lowest risk of death was observed with a moderate carbohydrate intake (50-55%). This is the intake recommended by current nutrition guidelines.

- The highest risk of death was observed with a low carbohydrate intake (<20%).

- The risk of death also increased with very high carbohydrate intake (>70%).

When the investigators used the mortality data to estimate life expectancy, they predicted a 50-year-old participant would have a projected life expectancy of:

- 33.1 years if they had a moderate intake of carbohydrates.

- 4 years less if they had a very low carbohydrate intake.

- 1.1 year less if they had a very high carbohydrate intake.

And the risk associated with low carbohydrate intake was affected by what the carbohydrate was replaced with.

- When carbohydrates were replaced with animal protein and animal fat there was an increased risk of mortality on a low-carb diet.

The animal-based low-carb diet contained more beef, pork, lamb, chicken, and fish. It was also higher in saturated fat.

- When carbohydrates were replaced with plant protein and plant fats, there was a decreased risk of mortality on a low-carb diet. The plant-based low-carb diet contained more nuts, peanut butter, dark or whole grain breads, chocolate, and white bread. It was also higher in polyunsaturated fats.

The effect of carbohydrate intake on mortality was virtually the same for all-cause mortality, cardiovascular mortality, and non-cardiovascular mortality.

There was no significant effect of carbohydrate intake on long-term weight gain (another myth busted).

The results from the dueling meta-analyses were actually very similar in some respects. When the data from all studies were combined:

Very high carbohydrate diets were associated with increased mortality.

Meat-based low-carb diets increased mortality, and plant-based low-carb diets decreased mortality.

The results were the same for total mortality, cardiovascular mortality, and non-cardiovascular mortality.

The authors concluded: “Our findings suggest a negative long-term association between life-expectancy and both low carbohydrate and high carbohydrate diets…These data also provide further evidence that animal-based low carbohydrate diets should be discouraged.

Alternatively, when restricting carbohydrate intake, replacement of carbohydrates with predominantly plant-based fats and proteins could be considered as a long-term approach to healthy aging.”

Simply put, that means if a low carb diet works best for you, it is healthier to replace the carbs with plant-based fats and protein rather than animal-based fats and protein.

The “Goldilocks Effect”

This study also resolved the discrepancies between previous studies. The authors pointed out that the PURE study relied heavily on data from Asian and developing countries, and the average carbohydrate intake is very different in Europe and the US than in Asian and developing countries.

In the US and Europe mean carbohydrate intake is about 50% of calories and it ranges from 25% to 70% of calories. With that range of carbohydrate intake, it is possible to observe the increase in mortality associated with both very low and very high carbohydrate intakes.

The US and European countries are affluent, which means that low carb enthusiasts can also afford diets high in animal protein.

In contrast, white rice is a staple in Asian countries, and protein is a garnish rather than a main course. Consequently, overall carbohydrate intake is greater in Asian countries and very few Asians eat a truly low carbohydrate diet.

High protein foods tend to be more expensive than high carbohydrate foods. Thus, very few people in developing countries can afford to follow a very low carbohydrate diet, and overall carbohydrate intake also tends to be higher in those countries.

Therefore, in Asian and developing countries the average carbohydrate intake is greater (~61%) than in the US and Europe (~50%), and the range of carbohydrate intake is from 45% to 80% of calories instead of 25% to 70%. With this range of intake, it is only possible to see the increase in mortality associated with very high carbohydrate intake.

In fact, when the authors of the current study overlaid the data from the PURE study with their ARIC data, there was an almost perfect fit. The only difference was that their ARIC data covered both low and high carbohydrate intake while the PURE study touted by low carb enthusiasts only covered moderate to high carbohydrate intake.

[I have given you my rendition of the graph on the right. If you would like to see the data yourself, look at the paper.]

Basically, low carb advocates are telling you that diets with carbohydrate intakes of 26% or less are healthy based on studies that did not include carbohydrate intakes below 40%. That is misleading. The studies they quote are incapable of detecting the risks of low carbohydrate diets.

In short, the ARIC study finally answered the question, “How much carbohydrate should we be eating if we desire a long and healthy life?” The answer is “Enough”.

I call this “The Goldilocks Effect”. You may remember “Goldilocks And The Three Bears”. One bed was too hard. One bed was too soft. But one bed was “just right”. One bowl of porridge was too hot. One was two cold. But one was “just right”.

According to this study, the same is true for carbohydrate intake. High carbohydrate intake is unhealthy. Low carbohydrate intake is unhealthy. But moderate carbohydrate intake is “just right”.

What Does This Study Mean For You?

There are several important take-home lessons from this study:

1) All major studies agree that very high carbohydrate intake is unhealthy. In part, that reflects the fact that diets with high carbohydrate intake are likely to be high in sodas and sugary junk foods. It may also reflect the fact that diets which are high in carbohydrates are often low in plant protein or healthy fats or both.

2) All studies that cover the full range of carbohydrate intake agree that low and very low carbohydrate diets are also unhealthy. They shorten the life expectancy of a 50-year-old by about 4 years.

3) The studies quoted by low carb enthusiasts to support their claim that low-carb and very low carb diets are healthy don’t include carbohydrate intakes below 40%. That means their claims are misleading. The studies they quote are incapable of detecting the risks of low carbohydrate diets. Their claims are a myth.

4) Not all high carb diets are created equally. As I noted above, the Mediterranean and DASH diets are just as high in carbohydrates as the typical American diet, but their carbohydrates come from whole fruits and vegetables, whole grains, beans, nuts, and seeds. And multiple studies show that both diets are much healthier than the typical American diet.

5) Not all low carb diets are created equally. Meat-based low-carb diets decrease life expectancy compared to the typical American diets while plant-based low carb diets increase life expectancy.

6) The health risks of meat-based low-carb diets may be due to the saturated fat content or the heavy reliance on red meat. However, the risks are just as likely to be due to the foods these diets leave out – typically fruits, whole grains, legumes, and some vegetables.

7) Proponents of low-carb diets assume that you can make up for the missing nutrients by just taking multivitamins. However, each food group also provides a unique combination of phytonutrients and fibers. The fibers, in turn, influence your microbiome. Simply put, whenever you leave out whole food groups, you put your health at risk.

The Bottom Line

The low-carb wars are raging. Several studies have reported that low carb diets increase risk of mortality (shorten lifespan). However, a study published a few years ago came to the opposite conclusion. That study had low carb enthusiasts doing a victory lap and claiming it is time to rewrite nutritional guidelines to favor low-carb diets.

However, a study published a year later resolves the conflicting data and finally answers the question: “How much carbohydrate should we be eating if we desire a long and healthy life?” The answer is “Enough”.

I call this “The Goldilocks Effect”. According to this study, high carbohydrate intake is unhealthy. Low carbohydrate intake is unhealthy. But moderate carbohydrate intake is “just right”.

Specifically, this study reported:

Moderate carbohydrate intake (50-55%) is healthiest. This is the carbohydrate intake found in healthy diets like the Mediterranean and DASH diets, and is the intake recommended by current nutritional guidelines.

All major studies agree that very high carbohydrate intake (60-70%) is unhealthy. It shortens the life expectancy of a 50-year-old by about a year.

All studies that cover the full range of carbohydrate intake agree that low carbohydrate intake (<26%) is also unhealthy. It shortens the life expectancy of a 50-year-old by about 4 years.

The studies quoted by low carb enthusiasts to support their claim that low-carb diets are healthy don’t include carbohydrate intakes below 40%. That means their claims are misleading. The studies they quote are incapable of detecting the risks of low carbohydrate diets.

Meat-based low-carb diets decrease life expectancy while plant-based low carb diets increase life expectancy. This is consistent with the results of previous studies.

Simply put, the latest study means that the supposed benefits of low carb diets are a myth.

For more details, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

___________________________________________________________________________

For more detail about FTC regulations for health claims, see this link.

https://www.ftc.gov/business-guidance/resources/health-products-compliance-guidance

______________________________________________________________________

About The Author

Does Diet Matter For Weight Loss?

December 31, 2024 by Dr. Steve Chaney

Who Benefits Most From A Healthy Diet?

Author: Dr. Stephen Chaney

Fad diets abound. High protein, low carb, low fat, vegan, keto, paleo – the list is endless. They all claim to be backed by scientific studies showing that you lose weight, lower your cholesterol and triglycerides, lower your blood pressure, and smooth out your blood sugar swings.

They all claim to be the best. But any reasonable person knows they can’t all be the best. Someone must be lying.

My take on this is that fad diet proponents are relying on “smoke and mirrors” to make their diet look like the best. I have written about this before, but here is a brief synopsis:

They compare their diet with the typical American diet.

- Anything looks good compared to the typical American diet.

- Instead, they should be comparing their diet with other weight loss diets. That is the only way we can learn which diet is best.

They are all restrictive diets.

- Any restrictive diet will cause you to eat fewer calories and to lose weight.

- And as little as 5% weight loss results in lower cholesterol & triglycerides, lower blood pressure, and better control of blood sugar levels.

Simply put, any restrictive diet will give you short-term weight loss and improvement in blood parameters linked to heart disease, stroke, and diabetes. But are these diets healthy long term? For some of them, the answer is a clear no. Others are unlikely to be healthy but have not been studied long term. So, we don’t know whether they are healthy or not.

What if you started from the opposite perspective? Instead of asking, “Is a diet that helps you lose weight healthy long term?”, what if you asked, “Does the diet you choose matter for weight loss? Can healthy eating help you lose weight?” The study (S Schutte et al, American Journal of Clinical Nutrition, 115: 1-18, 2022)) I will review this week asked these question.

This was an excellent study. It compared a healthy diet to an unhealthy diet with the same degree of caloric restriction. And it compared both diets to the habitual diet of people in that area. This study was performed in the Netherlands, so both weight loss diets were compared to the habitual Dutch diet.

How Was The Study Done?

Had diabetes.
Smoked.
Had a diagnosed medical condition.
Were on a medication that interfered with blood sugar control.
Were on a vegetarian diet.

The participants were randomly assigned to:

A high-nutrient quality diet that restricted calories by 25%.
A low-nutrient-quality diet that restricted calories by 25%.
A continuation of their habitual diet.

At the beginning and end of the study the participants were weighed, and cholesterol, triglycerides, and blood pressure were measured.

Does Diet Matter For Weight Loss?

To put this study into context, these were not healthy and unhealthy diets in the traditional sense.

Both were whole food diets.
Both included fruits, vegetables, low-fat dairy, and lean meats.
Both restricted calories by 25%.

The diets were designed so that the “high-nutrient quality” diet had significantly more plant protein (in the form of soy protein), fiber, healthy fats (monounsaturated and omega-3 fats), and significantly less fructose and other added sugars than the “low-nutrient-quality” diet.

When the investigators measured weight loss at the end of 12 weeks:

Participants lost significant weight on both calorie-restricted diets compared to the group that continued to eat their habitual diet.

- That is not surprising. Any diet that successfully restricts calories will result in weight loss.

Participants on the high-nutrient quality diet lost 33% more weight than participants on the low-nutrient-quality diet (18.5 pounds compared to 13.9 pounds).

Participants on the high-nutrient quality diet lost 50% more inches in waist circumference than participants on the low-nutrient-quality diet (1.8 inches compared to 1.2 inches).

- Waist circumference is a direct measure of abdominal obesity.

When the investigators measured blood pressure, fasting total cholesterol levels, and triglyceride levels at 12 weeks:

These cardiovascular risk factors were significantly improved on both diets.

- Again, this would be expected. Any diet that causes weight loss results in an improvement in these parameters.

However, the reduction in total serum cholesterol was 2.5-fold greater and the reduction in triglycerides was 2-fold greater in the high-nutrient quality diet group than in the low-nutrient-quality diet group.

And the reduction in systolic blood pressure was 2-fold greater and the reduction in diastolic blood pressure was 1.67-fold greater in the high-nutrient quality diet group than in the low-nutrient-quality diet group.

In short, participants in this study lost more weight and had a better improvement in risk factors for heart disease on a high-nutrient-quality diet than on a low-nutrient-quality diet. Put another way, diet does matter for weight loss. Healthy eating helped them lose more weight and gave them greater improvement in their health.

Who Benefits Most From A Healthy Diet?

None of the participants in this study had been diagnosed with diabetes when the study began. However, all of them were middle-aged, overweight, and had abdominal obesity. That means many of them likely had some degree of insulin resistance.

Because of some complex metabolic studies that I did not describe, the investigators suspected that insulin resistance might influence the relative effectiveness of the two energy-restricted diets.

To test this hypothesis, they used an assay called HOMA-IR (homeostatic model assessment of insulin resistance). Simply put, this assay measures how much insulin is required to keep your blood sugar under control.

They used a HOMA-IR score of 2.5 to categorize insulin resistance among the participants.

Participants with a HOMA-IR score >2.5 were categorized as insulin-resistant. This was 55% of the participants.

Participants with a HOMA-IR score ≤2.5 were categorized as insulin-sensitive. This was 45% of the participants.

When they used this method to categorize participants they found:

Insulin-resistant individuals lost about the same amount of weight on both diets.

Insulin-sensitive individuals lost 66% more weight on the high-nutrient-quality diet than the low-nutrient-quality diet (21.6 pounds compared to 13.0 pounds).

The investigators concluded, “Overweight, insulin-sensitive subjects may benefit more from a high- than a low-nutrient-quality energy-restricted diet with respect to weight loss…”

What Does This Study Mean For You?

Simply put this study confirms that:

Caloric restriction leads to weight loss, and…

Weight loss leads to improvement in cardiovascular risk factors like total cholesterol, triglycerides, and blood pressure.

- This is not new.

- This is true for any diet that results in caloric restriction.

However, this study breaks new ground in that it shows a high-nutrient quality diet results in significantly better…

Weight loss and…

Reduction in cardiovascular risk factors….

…compared to a low-nutrient quality diet with the same degree of caloric restriction.

As I said above, the distinction between a “high-nutrient-quality” diet and a “low-nutrient-quality” diet may not be what you might have expected.

Both diets were whole food diets. Neither diet allowed sodas, sweets, and highly processed foods.

Both included fruits, vegetables, grains, and lean meats.

Both reduced caloric intake by 25%.

- If you want to get the most out of your weight loss diet, this is a good place to start.

However, in this study the investigators designed their “high-nutrient-quality” diet so that it contained:

More plant protein in the form of soy protein.

- In this study they did not reduce the amount of animal protein in the “high-nutrient-quality” diet. They simply added soy protein foods to the diet. I would recommend substituting soy protein for some of the animal protein in the diet.

More fiber.

- The additional fiber came from substituting whole grain breads and brown rice for refined grain breads and white rice, adding soy protein foods, and adding an additional serving of fruit.

More healthy fats (monounsaturated and omega-3 fats).

- The additional omega-3s came from adding a fish oil capsule providing 700mg of EPA and DHA.

Less added sugar.

- While this study focused on fructose, their high-nutrient-quality diet was lower in all added sugars.

All these changes make great sense if you are trying to lose weight.

I would group these changes into 7 recommendation

1) Follow a whole food diet. Avoid sodas, sweets, and highly processed foods.

2) Include all 5 food groups in your weight loss diet. Fruits, vegetables, whole grains, dairy, and lean proteins all play an important role in your long-term health.

4) Eat a diet high in natural fiber. Including fruits, vegetables, whole grains, beans, nuts, seeds, and soy foods in your diet is the best way to achieve this goal.

6) Reduce the amount of added sugar, especially fructose, from your diet. That is best achieved by eliminating sodas, sweets, and highly processed foods from the diet. I should add that fructose in fruits and some healthy foods is not a problem. For more information on that topic, I refer you to a previous “Health Tips” article.

7) Finally, I would like to remind you of the obvious. No diet, no matter how healthy, will help you lose weight unless you cut back on calories. Fad diets achieve that by restricting the foods you can eat. In the case of a healthy diet, the best way to do it is to cut back on portion sizes and choose foods with low caloric density.

Finally, I should touch briefly on the third major conclusion of this study, namely that the “high-nutrient quality diet” was not more effective than the “low-nutrient-quality” diet for people who were insulin resistant. In one sense, this was not news. Previous studies have suggested that insulin-resistant individuals have more difficulty losing weight. That’s the bad news.

However, there was a silver lining to this finding as well:

Only around half of the overweight, abdominally obese adults in this study were highly insulin resistant.

- That means there is a ~50% chance that you will lose more weight on a healthy diet.

More importantly, because both diets restricted calories by 25%, insulin-resistant individuals lost weight on both diets.

- That means you can lose weight on any diet that successfully reduces your caloric intake even if you are insulin resistant. That’s the good news.

However, my recommendation would still be to choose a high-nutrient quality diet that is designed to reduce caloric intake, because that diet is more likely to be healthy long term.

The Bottom Line

A recent study asked, “Can healthy eating help you lose weight?” This study was a randomized controlled study, the gold standard of clinical studies. The participants were randomly assigned to:

A high-nutrient quality diet that restricted calories by 25%.
A low-nutrient-quality diet that restricted calories by 25%.
Continue with their habitual diet.

These were not healthy and unhealthy diets in the traditional sense.

Both were whole food diets.
Both included fruits, vegetables, low-fat dairy, and lean meats.
Both restricted calories by 25%.

The diets were designed so that the “high-nutrient quality” diet had significantly more plant protein (in the form of soy protein), fiber, healthy fats (monounsaturated and omega-3 fats), and significantly less fructose and other added sugars than the “low-nutrient-quality” diet.

At the end of 12 weeks:

Participants on the high-nutrient quality diet lost 33% more weight and had better cardiovascular markers than participants on the low-nutrient-quality diet.

In short, participants in this study lost more weight and had a better improvement in risk factors for heart disease on a high-nutrient-quality diet than on a low-nutrient-quality diet. Put another way, diet does matter for weight loss. Healthy eating helped them lose more weight and gave them greater improvement in their heart health.

For more details on this study, what this study means for you, and my 7 recommendations for a healthy weight loss diet, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease.

______________________________________________________________________________

For more detail about FTC regulations for health claims, see this link.

https://www.ftc.gov/business-guidance/resources/health-products-compliance-guidance

_______________________________________________________________________

About The Author

Dr. Chaney won numerous teaching awards at UNC, including the Academy of Educators “Excellence in Teaching Lifetime Achievement Award”.

600th Issue Celebration

November 5, 2024 by Dr. Steve Chaney

Nutrition Advances Over The Last Two Years

Author: Dr. Stephen Chaney

In the nearly twelve years that I have been publishing “Health Tips From The Professor”, I have tried to go behind the headlines to provide you with accurate, unbiased health information that you can trust and apply to your everyday life.

The 600^th issue of any publication is a major cause for celebration and reflection – and “Health Tips From The Professor” is no different.

I am dedicating this issue to reviewing some of the major stories I have covered in the past 100 issues. There are lots of topics I could have covered, but I have chosen to focus on three types of articles:

Articles that have debunked long-standing myths about nutrition and health.

Articles that have corrected some of the misinformation that seems to show up on the internet on an almost daily basis.

Articles about the issues that most directly affect your health.

Here are my picks from the last two years:

Weight Loss Diets

Since it is almost January, let’s start with a couple of articles about diet and weight loss (or weight gain). I have covered the effectiveness of the Paleo, Keto, Mediterranean, DASH, vegetarian, and Vegan diets for both short and long-term weight loss in my book “Slaying The Food Myths”, so I won’t repeat that information here. Instead, I will share a few updates from the past 100 issues.

Is Time-Restricted Eating Better Than Other Diets? Time-restricted eating is one of the latest fads. But is it really better than other diets for weight loss and improved health? In this article I reviewed two studies that compare time-restricted eating with diets that do not restrict time of eating but cut calories to the same extent. You may be surprised at the results.

Can You Lose Weight Without Dieting? In this article I share 8 tips for losing weight without going on a diet. The article is based on research by Dr. Brian Wansink, a behavioral psychologist who specializes in studying how external clues influence our eating patterns. As you might suspect his 8 tips for losing weight have nothing to do with counting calories or going on restrictive diets.

Healthy Diets

Is Whole Fat Dairy Healthy? For years dietary guidelines have been telling us to select low fat dairy foods. But some health gurus are telling you that isn’t true. They claim whole fat dairy is healthy. So, you are probably wondering, “What is the scoop (as in ice cream) on whole fat dairy?” In this article I look at the study behind the headlines and answer that question. But the answer is not a simple “Yes” or “No”. The answer is more nuanced. It turns out that whole fat dairy is healthier in some diets than in others.

Are Low Carb Diets Healthy? Are low carb diets good for you or bad for you? It depends on which study you quote. Two major studies in recent years have come to opposite conclusions. In this article I help you sort through the conflicting studies and rephrase the question. Instead of, “Are low carb diets healthy”, the question should be, “Which low carb diets are healthy?”

Are All Plant-Based Diets Healthy? Plant-based diets have acquired a “health halo” in recent years. Your mama told you to eat your fruits and vegetables. And many health gurus have been telling you not to neglect your grains, legumes, nuts, and seeds as well. But some of these foods require a lot of food preparation.

Never fear! The food industry has come to your rescue with a wide variety of processed plant-based foods. No need for food prep. But are they as good for you as the unprocessed plant foods they replace? In this article I review a study that answers that question.

You probably know what that answer is, but the article is worth a read anyway. That is because the study also asks whether vegan and vegetarian diets are healthier than other primarily plant-based diets. And you may not know the answer to that question.

Diet And Heart Disease

Are Eggs Bad For You? For years we were told that eggs are bad for us because they contain cholesterol. Then we were told that eggs in moderation may not increase our risk of heart disease. And recently studies have appeared claiming eggs may be good for our hearts. What is the truth about eggs and heart disease? In this article I review a recent study claiming eggs are bad for our heart and put that study into the context of other recent studies to clear up the “eggfusion”.

Which Diets Are Heart Healthy? Every popular diet claims to help you lose weight, reduce your risk of diabetes, and reduce your risk of heart disease. All these claims can’t be true. Which diets deliver on their promises, and which are just pretenders? In this article I review a recent study that answered that question for heart disease.

This study was a very large metanalysis of over 40 studies with 35,548 participants that looked at the effect of different diets on heart disease outcomes. The study identified two diets that significantly reduced the risk of heart disease. There are other diets that might reduce the risk of heart disease, but their benefits have not been proven by high quality clinical studies. They are merely pretenders.

The Dangers Of Processed Foods

In previous issues of “Health Tips From the Professor” I have shared articles showing that diets high in processed foods are associated with an increased risk of obesity, diabetes, and heart disease. But the story keeps getting worse. Here are two articles on recent studies about processed foods that appeared in “Health Tips From The Professor” in the last two years.

Why Does Processed Food Make You Fat? We already know that eating a lot of highly processed food is likely to make us fat. But what is it about processed food that makes us fat? In this article I review a recent study that answers that question.

This study is interesting for two reasons.

It identifies the characteristics of processed foods that make us want to eat more.

It identifies some minimally processed foods that have the same characteristics and suggests we should choose minimally processed foods wisely. Simply put, knowledge is power. We may want to avoid minimally processed foods that have the same obesity-inducing characteristics as processed foods.

Do Processed Foods Cause Cancer? Previous studies have shown that processed food consumption is associated with a higher risk of obesity, diabetes, and heart disease. Can it get any worse? In this article I review a recent study that shows processed food consumption is associated with an increased risk of several kinds of cancer.

Maintaining Muscle Mass As We Age

As we age, we begin to lose muscle mass, a process called sarcopenia. Unless we actively resist loss of muscle mass it will eventually impact our quality of life and our health.

We can prevent this loss of muscle mass with resistance exercise, adequate protein intake, and adequate intake of the amino acid leucine. Previous studies have shown people over 50 need more of each of these to maintain muscle mass, but the amount they need has been uncertain until now. Three recent studies have given seniors better guidelines for maintaining muscle mass.

Can You Build Muscle In Your 80s? In this article I review a recent study that enrolled a group of octogenarians in a high-intensity exercise program to see if they could gain muscle mass. They were able to increase their muscle mass, but the intensity of the exercise required may surprise you.

Optimizing Protein Intake For Seniors. In this article I review two recent studies that looked at the amount, timing, and kind of protein needed for seniors in their 60s and 70s to maximize gain in muscle mass.

How Much Leucine Do Seniors Need? In this article I review a recent study that determined the amount of leucine seniors in their 70s need to optimize gains in muscle mass and strength.

The Benefits And Risks Of Supplementation

If you listen to Big Pharma or the medical profession, you hear a lot about the “risks” of supplementation and very little about the benefits. In “Health Tips From the Professor” I try to present a more balanced view of supplementation by sharing high-quality studies showing benefit from supplementation and studies that put the supposed risks into perspective.

The Good News About Omega-3s and Stroke. Multiple studies have shown that omega-3 supplementation reduces the risk of ischemic strokes (strokes caused by a blood clot). But it has been widely assumed they might increase the risk of hemorrhagic strokes (strokes caused by bleeding). In this article I review a meta-analysis of 29 clinical studies with 183,000 participants that tested that assumption.

How Much Omega-3s Are Best For Blood Pressure? Multiple studies have shown that omega-3 supplementation can reduce high blood pressure. But the doses used vary widely from one study to the next. In this article I review a meta-analysis of 71 double-blind, placebo-controlled clinical studies that determined the optimal dose of omega-3s for controlling blood pressure.

Omega-3 Supplements Are Safe. As I said above, it has been widely assumed that omega-3 supplementation increases the risk of bleeding and hemorrhagic stroke. In this article I review the definitive study on this topic. More importantly, it reveals which omega-3 supplements might increase bleeding risk and which do not.

Are Calcium Supplements Safe? Big Pharma and the medical profession have been warning us that calcium supplements may increase heart disease risk. In this article I review the definitive study on this topic.

Prenatal Supplements

If you are pregnant or thinking of becoming pregnant, your health professional has likely recommended a prenatal supplement. You probably assume that prenatal supplements provide everything you need for a healthy pregnancy. Unfortunately, recent research has shown that assumption is not correct.

Is Your Prenatal Supplement Adequate? In this article I review a study that should serve as a wakeup call for every expectant mother. It showed that most prenatal supplements were woefully inadequate for a healthy pregnancy.

What Nutrients Are Missing In Prenatal Supplements? In this article I review a study that identified additional nutrients that are missing in most prenatal supplements.

Prenatal Supplements Strike Out Again. In this article I review a study that looked at the diet of pregnant women to determine their needs and compared that to the nutrients found in prenatal supplements. Once again, most prenatal supplements were woefully inadequate. Is it, “Three strikes and you are out”?

Exercise

Walking Your Way To Health. We have been told that walking is good for our health. But how many steps should you take, how fast should you walk, and does it matter whether these steps are part of your daily routine or on long hikes? In this article I review a study that answers all these questions.

Which Exercise Is Best For Reducing Blood Pressure? If you have high blood pressure, you have probably been told to exercise more. But which exercise is best? In this article I review a study that answers that question. And the answer may surprise you.

Did You Know?

If you have been reading “Health Tips From the Professor” for a while, you probably know that I enjoy poking holes in popular myths. Here are two new ones I deflated in past two years.

Is Low Alcohol Consumption Healthy? You have probably heard that low alcohol intake (that proverbial glass of red wine) is good for you. But is that true? In this article I review a recent study that shows that myth was based on faulty interpretation of the data and provides a more nuanced interpretation of the data.

Is HDL Good For Your Heart? You have been told that increasing your HDL levels reduces your risk of heart disease so many times it must be true. But is it? In this article I review HDL metabolism and a recent study to provide a more nuanced interpretation of the relationship between HDL and heart disease risk.

How To Talk With Your Doctor About Cancer

Because of my years in cancer research, I am often asked whether someone should follow their oncologist’s advice and go on a recommended chemotherapy or radiation regimen. Of course, it would be unethical for me to provide that kind of advice.

In this article I tell you the questions to ask your oncologist about the prescribed treatment regimen, so you can make an informed decision. However, I also recommend you only ask these questions if you can handle the answers.

The Bottom Line

I have just touched on a few of my most popular articles above. You may want to scroll through these articles to find ones of interest to you that you might have missed over the last two years. If you don’t see topics that you are looking for, just go to https://chaneyhealth.com/healthtips/ and type the appropriate term in the search box.

In the coming years, you can look for more articles debunking myths, exposing lies and providing balance to the debate about the health topics that affect you directly. As always, I pledge to provide you with scientifically accurate, balanced information that you can trust. I will continue to do my best to present this information in a clear and concise manner so that you can understand it and apply it to your life.

Final Comment: You may wish to share the valuable resources in this article with others. If you do, then copy the link at the top and bottom of this page into your email. If you just forward this email and the recipient unsubscribes, it will unsubscribe you as well.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease.

_______________________________________________________________________________

For more detail about FTC regulations for health claims, see this link.

https://www.ftc.gov/business-guidance/resources/health-products-compliance-guidance

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About The Author

Do Bad Genes Doom You To Bad Health?

October 1, 2024 by Dr. Steve Chaney

The Influence Of Genetics And Diet On Type 2 Diabetes

Author: Dr. Stephen Chaney

Does it ever feel like you have drawn the short straw?

Everyone in your family has succumbed to heart disease, diabetes, or cancer at a young age. Are you doomed to the same fate?

You ordered a DNA test. It sounded like fun. But when the gene report came back it said you had a “bad” genetic profile. You were told you are at high risk of diabetes, heart attack, stroke, cancer, or dementia. Are you doomed to a short and sickly life?

In both cases, you are probably wondering, “Is there anything I can do to improve my odds of a healthy life? What if I lost some of those extra pounds, exercised more, and ate a healthier diet? Would that make a difference?”

The study (J Merino et al, PLoS Medicine 19(4): e1003972, April 26, 2022) I will describe today was designed to answer these questions.

But before I describe the study, I should probably cover what I call Genetics 101: “How Genes Affect Your Health”.

Genetics 101: How Genes Affect Your Health

If you studied genetics in school, you probably learned about diseases like sickle cell anemia, which is caused by a single mutation in a single gene. If you get two copies of the “bad” gene, you will have sickle cell anemia. If you get one copy of the “bad” gene and one copy of the normal gene, you have sickle cell trait, which is much less severe.

Simply put, you either have the disease or you don’t. It’s dependent on your genetics, and you can’t do much about it.

If you know someone who has been treated for breast cancer, you are probably familiar with a more complex relationship between genetics and health. There are several “bad” genes that increase the risk of breast cancer. And knowing which gene is involved is important for selecting the best treatment regimen.

But most of the diseases that shorten our lives (like diabetes, heart disease, most cancers, and dementia) are what we call polygenetic diseases. Simply put, that means that there are dozens of genes that increase the risk of these diseases. Each gene makes a small contribution to the increased risk. So, we can only measure the genetic contribution to these diseases by measuring hundreds of mutations in dozens of genes, something called a polygenetic risk score.

The study I will be describing today looked at the relative effect of genetics (measured as the type 2 diabetes polygenic risk score) and diet quality (measured as the Alternative Healthy Eating Index (AHEI)) on the risk of developing type 2 diabetes.

How Was This Study Done?

The data for this study were obtained from 3 long-term clinical studies conducted in the United States – the Nurses’ Health Study (121,700 participants), the Nurses’ Health Study II (116,340 participants), and the Health Professionals Follow-Up Study (51,529 participants).

These studies measured lifestyle factors (including diet) every 4 years and correlated them with disease outcomes over 20+ years.

The study I will be discussing today was performed with 35,759 participants in these 3 studies for whom DNA sequencing data was available.

The DNA sequence data were used to generate a type 2 diabetes polygenic risk score for each participant in this study.

Food frequency questionnaires obtained every 4 years in these studies were used to calculate the Alternative Healthy Eating Index (AHEI) score for each participant.

- The AHEI is based on higher intake of fruits, whole grains, vegetables, nuts and legumes, polyunsaturated fatty acids, long-chain omega-3 fatty acids, moderate intake of alcohol, and lower intake of red and processed meats, sugar sweetened drinks and fruit juice, sodium, and trans-fat).

The investigators used these measurements to estimate the relative effect of genetics and diet quality on the risk of developing type 2 diabetes.

The Influence Of Genetics And Diet On Type 2 Diabetes

The participants were divided into low, intermediate, and high genetic risk based on their type 2 diabetes polygenic risk score.

Compared with low genetic risk:

Intermediate genetic risk increased the risk of developing type 2 diabetes by 26%.

High genetic risk increased the risk of developing type 2 diabetes by 75%.

Put another way, each 1 standard deviation increase in the polygenetic risk score:

Increased the risk of developing type 2 diabetes by 42%.

Simply put, bad genes can significantly increase your risk of developing type 2 diabetes. That’s the bad news. But that doesn’t mean you should think, “Diabetes is in my genes. There is nothing I can do.”

The investigators also divided the participants into those who had a high-quality diet, those who had an intermediate quality diet, and those who had a low-quality diet based on their AHEI (Alternative Healthy Eating Index) score.

Finally, they divided the participants into groups depending on their BMI, a measure of obesity.

Compared to an obese person consuming a low-quality diet, a lean person consuming a high-quality diet:

Reduced their risk of developing type 2 diabetes by around 43% for each category of genetic risk.

More specifically, a lean person consuming a high-quality diet reduced their risk of developing type 2 diabetes:

- By 41% if they were at low genetic risk.

- By 50% if they were at intermediate genetic risk.

- By 38% if they were at high genetic risk.

The investigators then made a statistical adjustment to remove BMI from their calculations, so they could focus on the effect of diet alone on the risk of developing type 2 diabetes.

Compared to a low-quality diet, a high-quality diet:

Reduced the risk of developing type 2 diabetes by around 33% for each category of genetic risk.

More specifically, a high-quality diet reduced the risk of developing type 2 diabetes:

- By 31% for those at low genetic risk.

- By 39% for those at intermediate genetic risk.

- By 29% for those at high genetic risk.

Looking at it another way:

When people at high genetic risk consumed a high-quality diet, their risk of developing type 2 diabetes was only 13% higher than people at intermediate genetic risk who consumed a low-quality diet (such as the typical American diet).

When people at intermediate genetic risk consumed a high-quality diet, their risk of developing type 2 diabetes was 5% less than people at low genetic risk who consumed a low-quality diet.

Simply put:

If you are at intermediate genetic risk, a high-quality diet may completely reverse your risk of developing type 2 diabetes.

If you are at high genetic risk, a high-quality diet can partially reverse your risk of developing type 2 diabetes.

In short, the good news is that bad genes do not doom you to type 2 diabetes.

The investigators did not provide similar information for the effect of an ideal weight on the risk of developing type 2 diabetes, but it is likely that the combination of diet plus weight management would result in an even more significant reduction in risk of developing type 2 diabetes for individuals in the even the highest risk category.

The authors concluded, “These data provide evidence for the independent associations of genetic risk and diet quality with incident type 2 diabetes and suggest that a healthy diet is associated with lower diabetes risk across all levels of genetic risk.”

Do Bad Genes Doom You To Bad Health?

At the beginning of this article I posed the question, “Do bad genes doom you to bad health?”

Based on this study, the good news is that bad genes don’t doom you type 2 diabetes. And just because most of your relatives are diabetic doesn’t mean that must be your fate.

This study shows that a healthy diet significantly reduces your risk of developing type 2 diabetes at every genetic risk level.

And the study suggests that a healthy diet plus a healthy weight is even more beneficial at reducing your risk of type 2 diabetes.

While not included in this study, other studies have shown that exercise also plays a role in reducing type 2 diabetes risk.

None of this information is new. What is new is that a healthy diet is equally beneficial at reducing type 2 diabetes risk even in individuals with a high genetic risk of developing the disease. Simply put, you can reverse the effects of bad genes.

“And what is this magic diet?”, you might ask. In this study, it was based on AHEI score. Someone with a high AHEI score consumes:

Lots of fruits, whole grains, vegetables, nuts and legumes, polyunsaturated fatty acids, and long-chain omega-3 fatty acids.

Moderate or no amounts of alcohol.

Little or no red and processed meats, sugar sweetened drinks, fruit juices, sodium, and foods with trans-fat.

Any whole food, primarily plant-based diet from vegan to Mediterranean or DASH fits the bill.

Finally, while this study focused just on type 2 diabetes, other studies have come to similar conclusions for other diseases.

Should You Get Your DNA Tested?

If you are looking for guidance on how to reduce your risks, the answer is, “No”. In this study, the same diet and lifestyle changes lowered the risk of type diabetes at every genetic risk level. Despite what some charlatans may tell you, there is no special diet or magic potion for people with a high genetic risk for developing type 2 diabetes.

If you are looking for motivation, the answer may be, “Yes”. If knowing you are at high risk makes it more likely that you will make the diet and lifestyle changes needed to lower your risk of type 2 diabetes, a DNA test may be just what you need

The Bottom Line

If a serious disease runs in your family or if you have had your DNA tested and found out you are at high risk for some disease, you are probably wondering whether there is anything you can do or whether your bad genes have doomed you to a short and sickly life.

A recent study answered that question for type 2 diabetes. It showed a healthy diet significantly reduces the risk of type 2 diabetes even in people at high genetic risk of developing the disease.

Other studies have come to similar conclusions for other diseases. In short, bad genes don’t doom you to bad health.

For more details about the study and what it means for you, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease.

_____________________________________________________________________________

For more detail about FTC regulations for health claims, see this link.

https://www.ftc.gov/business-guidance/resources/health-products-compliance-guidance

_______________________________________________________________________

About The Author

Do Optimists Live Longer?

June 25, 2024 by Dr. Steve Chaney

What Does This Study Mean For You?

Author: Dr. Stephen Chaney

You have probably heard the statement that optimists live longer before. In fact, you have probably heard so many times you assume it must be true. But is it a myth or is it the truth?

This question is important because it can affect how people feel about themselves. If you are a natural optimist, statements like this support your feeling of self-worth. But if you are naturally pessimistic, statements like this provide one more reason to feel bad about yourself.

For example, a recent article on the topic in WebMD starts with the statement, “Want to live longer? You might want to try improving your outlook on life.” I am mostly optimistic, so I find this statement to be positive and encouraging.

But I am not sure I would feel about this statement if I were pessimistic or depressed and had tried for years to be more optimistic.

Because of this it is important to ask, “How good is the evidence supporting this claim?”

There are several published studies supporting this claim (For example). However,

Most of these studies have been performed with white, high-income participants. It is not clear whether these same results would apply to other racial and ethnic groups.

There is also the “chicken versus egg” conundrum. The studies claiming that optimists live longer are all association studies. Simply put, that means optimism is associated with longevity, but does not prove cause and effect. That is important because:

- Some studies show that both a healthy diet and exercise improve mood.

- Other studies show that optimists tend to take better care of themselves, and that includes both diet and exercise.

- So, it’s hard to know which comes first – a healthy lifestyle, which creates optimism, or optimism, which creates a healthy lifestyle.

Because of this “chicken versus egg” conundrum, it is not clear whether it is a healthy lifestyle or optimism that is the primary cause of greater longevity.

The study (HK Koga et al, Journal of the American Geriatrics Society, 70: 2793-2804, 2022)) I will review today was designed to answer both questions. Specifically, this study was designed to ask:

Is higher optimism associated with a longer lifespan and exceptional longevity across diverse racial and ethnic groups?

To what extent do lifestyle factors influence this association?

How Was The Study Done?

The data for this study was obtained from the Women’s Health Initiative which enrolled 161,808 postmenopausal women of diverse racial and ethnic groups from 40 medical centers within the United States between 1993 and 1998. The women were aged 50-79 (average = 63.5) at enrollment and were followed for an average of 26 years.

Optimism was assessed at enrollment into the program using the 6-item Life Orientation Test Revised. For each item on the questionnaire, participants were asked to report the degree they agreed with each statement on a scale of 1 = “strongly agree” to 5 = “strongly disagree”. Their responses were summed to create scores ranging from 6 to 30, with 30 being the highest optimism rating.

Lifestyle was assessed on a questionnaire measuring diet quality, physical activity, BMI (a measure of obesity), smoking status, and alcohol consumption. If participants met predefined “healthy standards in each of these categories, they were given a score of 1. Otherwise, their score was 0. Scores from each category were summed to create a composite lifestyle score ranging from 0 (least healthy) to 5 (most healthy).

Longevity was based on survival compared to national averages using the National Death Index (Yes, “Big Brother” is watching you even when you die) to identify and confirm deaths. Deaths of participants were monitored through March 1, 2019. Exceptional longevity was defined as survival to age 90 or older. Overall, 64,301 women (40.3%) died over the 26 years of follow-up.

Finally, women who died within the first 2 years of follow-up were excluded from the data analysis “to mitigate concerns that health status might affect the reporting or experience of optimism levels.” In plain English, people who are within 2 years of dying are often very sick and feel lousy. Even the most optimistic individuals find it hard to maintain an optimistic outlook in those circumstances. This left 159,255 women in the database.

Do Optimists Live Longer?

When comparing women in the highest to women in the lowest quartile of optimism:

Longevity was increased by 5.4%, which corresponds to an additional 4.4 years. When this was broken down by race and ethnicity, longevity was increased by:

- 1% for Non-Hispanic White women.

- 6% for Black women.

- 4% for Hispanic women.

- 5% for Asian women. However, this may have been an underestimate because of the small sample size of this population in the Women’s Health Initiative database.

Exceptional longevity (survival ≥ 90 years) was increased 10%.

When the authors used a complex statistical method to assess the contribution of lifestyle to the increase in longevity, they found:

Lifestyle contributed to 24% of the increased longevity. When this was broken down by race and ethnicity, lifestyle contributed:

- 25% for Non-Hispanic White women.

- 10% for Black women.

- 24% for Hispanic women.

- 43% for Asian women.

The authors concluded, “We found that higher levels of optimism were associated with longer lifespan and greater likelihood of achieving exceptional longevity across racial and ethnic groups, suggesting the health benefits of optimism may hold across these groups.”

“The contribution of lifestyle to these associations was evident but modest.”

“As prior work has demonstrated that optimism is modifiable, it may be a novel target for interventions that aim to extend lifespan across diverse racial and ethnic groups.”

What Are The Strengths And Weaknesses Of This Study?

This is not the first study to suggest that optimists live longer. But it is the best study to date because:

It was larger (159,255 participants) than most previous studies.

It followed the participants far longer (26 years) than previous studies.

It included a more racially and ethnically diverse group of participants than previous studies.

It addressed the “elephant in the room” for studies of this type, namely that optimists tend to actively seek a healthier lifestyle, so the “benefits” of optimism could be due to a healthy lifestyle rather than a state of mind. The study employed statistics to estimate that a healthy lifestyle contributed around 25% to the longevity experienced by optimists.

However, the study did have some weaknesses. In my opinion, the most important weaknesses were:

Optimism and lifestyle were only assessed at the beginning of the study. No effort was made to determine whether either of these important variables changed during the 26-year study.

The relative influence of lifestyle and optimism on longevity was based on a complex statistical analysis. As Mark Twain said, “There are lies, damn lies, and statistics.” Simply put, statistics can sometimes give misleading answers. I would like to see this very important part of the study confirmed using a different method of analysis.

What Does This Study Mean For You?

As I shared above, I have some misgivings about this and other studies claiming that optimists live longer. But let’s assume this claim is true. What does that mean for you?

A 5.4% increase in lifespan might not sound like much, but it added 4.4 years to the lives of the women in the study. What would you do with an extra 4.4 years?

And, as the authors of the study pointed out, that’s equivalent to the gain in lifespan for adults engaged in a regular exercise program. Are those benefits addible? We don’t know, but it is possible that an optimist who exercised regularly and had a healthy diet might experience more than a 4-year gain in lifespan.

The authors said, “Although optimism is partly heritable (23-32%), experimental research has demonstrated that optimism is modifiable…”

Let me share a few things that have helped me maintain a more optimistic outlook:

Affirmations and visualizations of a positive future.

I start my daily prayers by listing the things I am grateful for. For others, a gratitude journal works equally well.

Accept positive input. You can accept compliments with humility by simply thanking the person for the compliment. But in your mind, use the compliment to overcome your inner doubts of self-worth.

Question negative input. Ask if each critic is the kind of person you want to become. If so, ask if what they said is really true.

Create a support network. These are family and friends who will support you when you need it and will give you a gentle kick in the …. when you need that.

Trust in a higher power. I know from experience that it is only God who can give me the “peace that passes all understanding” in my most difficult circumstances. And while I am Christian, I think this is a cornerstone of most religions.

Finally, I know that many people are predisposed to depression and pessimism, so I don’t want to be like the author of the WebMD article and tell you, “Want to live longer? You might want to try improving your outlook on life.”

We know that a healthy lifestyle is associated with longevity. And you don’t have to be an optimist to choose a healthy diet, exercise regularly, avoid smoking and excess alcohol intake, and get regular health check-ups.

We also know these things are associated with a longer healthspan which, simply put, is the number of years you live in good health.

So, whether you are a pessimist or an optimist you can live healthier longer.

The Bottom Line

You have probably heard that optimists live longer, but is it true? In the article above I describe the latest study on this topic. It is better than most previous studies on this topic because:

It was larger (159,255 participants) than most previous studies.

It followed the participants far longer (26 years) than previous studies.

It included a more racially and ethnically diverse group of participants than previous studies.

It addressed the “elephant in the room” for studies of this type, namely that optimists tend to actively seek a healthier lifestyle, so the “benefits” of optimism could be due to a healthy lifestyle rather than a state of mind. The study employed statistics to estimate that a healthy lifestyle contributed around 25% to the longevity experienced by optimists.

When the study compared women in the highest to women in the lowest quartile of optimism:

Longevity was increased by 5.4%, which corresponds to an additional 4.4 years.

Exceptional longevity (survival ≥ 90 years) was increased by 10%.

Lifestyle contributed to 24% of the increased longevity.

“As prior work has demonstrated that optimism is modifiable, it may be a novel target for interventions that aim to extend lifespan across diverse racial and ethnic groups.”

For more details on this study and what it means for you, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

______________________________________________________________________________

For more detail about FTC regulations for health claims, see this link.

https://www.ftc.gov/business-guidance/resources/health-products-compliance-guidance

______________________________________________________________________

About The Author

Dr. Chaney won numerous teaching awards at UNC, including the Academy of Educators “Excellence in Teaching Lifetime Achievement Award”.

What Can Twins Tell Us About Diet?

January 30, 2024 by Dr. Steve Chaney

What Are The Pros And Cons Of Twin Studies?

Author: Dr. Stephen Chaney

Why is the advice on healthy diets so confusing? One blog claims the vegan diet is best. Another says it is the keto diet is best. The Mediterranean diet is popular, but other experts claim the DASH or MIND diet might be better. Blogs champion diets ranging from the familiar to downright weird.

If you try to keep up with the science, it seems like the science is constantly changing. Each week you see headlines saying the latest study shows diet “X” is best – and “X” keeps changing. Why is that? Why do studies on healthy diets keep coming up with conflicting conclusions?

I have discussed the strengths and weaknesses of clinical studies and why they provide conflicting results in detail in previous issues of “Health Tips From the Professor”. However, one factor I have not discussed in detail is the effect of genetics on how we utilize foods, something called nutrigenomics.

Simply put, we are all genetically different. The way we utilize foods is different. The effect that foods have on our bodies is different. I have touched on that briefly in a previous article discussing individual difference in blood sugar response to various foods. But that is just one of many examples.

We do not yet know enough about gene-nutrient interactions to use genomic data to accurately predict which diets are best. Again, I have covered that topic in a previous issue of “Health Tips From the Professor”. However, we do know that genetic differences have a big influence on which diet is best for us. And most clinical studies on diets do not even attempt to take genetic differences into account.

That is where twin studies come in. Identical twins (monozygotic twins) have an identical genetic makeup and usually have an identical environment until they become adults. So, when I saw an identical twin study (MJ Landry et al, JAMA Network Open, 6(11):e2344457, 2023) comparing a vegan diet (only plant foods) with an omnivorous diet (both animal and plant foods), I wanted to review it and share it with you.

How Was The Study Done?

Identical twins were recruited from the Stanford Twin Registry. Twenty-two identical twin pairs were chosen for this study. Their characteristics were average age = 40, BMI = 26% (moderately overweight), sex = 77% female, ethnicity = 73% white, followed by an approximately equal representation of Asian, black, multiracial, and Pacific Islander.

One unanticipated characteristic of this group of twins was that 70% of them still lived together and cooked together, so their environment was also very similar.

One twin of each pair was put on a healthy vegan diet and the other on a healthy omnivorous diet for 8 weeks. Both diets were designed by dietitians. The diets emphasized fruits, vegetables, and whole grains while limiting added sugars and refined grains.

Both diets were healthier than the diets the twins were eating prior to the study. Finally, the participants were not told how much to eat, and were not instructed to lose weight.

For the first four weeks the participants were provided with all their meals by a nationwide food delivery company. The participants were also provided with training on purchasing and preparing healthy foods for their diet. This prepared them for the last 4 weeks of the study in which they purchased and prepared their own meals.

Participants visited the Stanford Clinical and Translational Science Research Unit at the beginning of the study and at the end of weeks 4 and 8 for weight measurement and a fasting blood draw.

Adherence to the diets was measured by a series of unannounced interviews to administer a 24-hour dietary recall questionnaire. These were scheduled for the weeks they visited the clinic.

What Can Twins Tell Us About Diet?

Even though the sample size was small, there were three statistically significant results.

LDL-cholesterol was reduced by 12% for the twin on the vegan diet, while it remained unchanged for the twin on the omnivorous diet.

The fasting insulin level was reduced by 21% for the twin on the vegan diet, while it remained unchanged for the twin on the omnivorous diet. This suggests the twin on the vegan diet was experiencing improved blood sugar control after just 8 weeks.

The twin on the vegan diet lost 4 pounds in 8 weeks, while weight remained the same for the twin on the omnivorous diet. This occurred even though neither twin was instructed to eat less nor to lose weight. It is most likely a consequence of the lower caloric density of the vegan diet (See my discussion of caloric density in last week’s issue of “Health Tips From the Professor”.

The changes in LDL-cholesterol and fasting insulin were remarkable because none of the twins in this study had elevated LDL-cholesterol or problems with blood sugar control at the beginning of the study.

The authors of this study concluded, “In this randomized clinical trial of the cardiometabolic effects of omnivorous vs vegan diets in identical twins, the healthy vegan diet led to improved cardiometabolic outcomes compared with a healthy omnivorous diet. Clinicians can consider this dietary approach as a healthy alternative for their patients.”

[Let me decipher the term cardiometabolic for you. The decrease in LDL-cholesterol is associated with heart health – the cardio portion of the term. The decrease in fasting insulin is associated with decreased risk of diabetes. Since diabetes is considered a metabolic disease, this is the metabolic portion of the term.]

Were There Any Downsides To The Vegan Diet?

This study also highlighted two well-known limitations of vegan diets.

Although the differences were not statistically significant, the authors expressed concern that vitamin B12 intake was less for twins on the vegan diet than twins on the omnivorous diet even though the vegan diet was designed by dietitians.

The authors noted that B12 deficiency among vegans is well known, and said, “Long-term vegans are typically encouraged to take a cyanocobalamin (vitamin B12) supplement.

Although both groups had excellent adherence to their assigned diets, those assigned to the vegan diet expressed a lower satisfaction with the diet, which suggests long-term adherence to the diet after the study ended was unlikely.

The authors said, “Although our findings suggest that vegan diets offer a protective cardiometabolic advantage compared with a healthy omnivorous diet, excluding all meats and/or dairy products may not be necessary because research suggests that cardiometabolic benefits can be achieved with modest reduction in animal foods and increases in healthy plant-based foods compared with typical diets.”

“We believe that lower dietary satisfaction in the vegan group may have been attributable to the strictness of the vegan diet…Some people may find a less restrictive diet preferable for LDL-cholesterol-lowering effects.”

I concur.

What Are The Pros And Cons Of Twin Studies?

The Pros are obvious. Most dietary studies cannot take genetic differences into account and have difficulty accounting for environmental differences. In this study genetics was identical for each twin pair and their environment was very similar. It offers a unique advantage over other studies.

But the strength of this study is also its greatest weakness. Because the general population is genetically and environmentally diverse, it is difficult to extrapolate the results to the general population.

If this were the only study to show cardiometabolic benefits of a plant-based diet, it would simply be an interesting observation.

But there are several studies showing that the vegan diet is associated with lower weight and reduced risk of heart disease and diabetes.

And there are dozens of studies showing that primarily plant-based omnivorous diets reduce the risk of heart disease and diabetes.

This study is fully consistent with those studies.

The Bottom Line

A recent study put identical twins on either a healthy vegan diet (only plant foods) or a healthy omnivorous diet (both animal and plant foods) for 8 weeks. At the end of 8 weeks:

LDL-cholesterol was reduced by 12% for the twin on the vegan diet, while it remained unchanged for the twin on the omnivorous diet.

The fasting insulin level was reduced by 21% for the twin on the vegan diet, while it remained unchanged for the twin on the omnivorous diet. This suggests the twin on the vegan diet was experiencing improved blood sugar control after just 8 weeks.

The twin on the vegan diet lost 4 pounds in 8 weeks, while weight remained the same for the twin on the omnivorous diet. This occurred even though neither twin was instructed to eat less or to lose weight. It is most likely a consequence of the lower caloric density of the vegan diet.

The changes in LDL-cholesterol and fasting insulin were remarkable because none of the twins in this study had elevated LDL-cholesterol or problems with blood sugar control at the beginning of the study.

For more information on the pros and cons of this study and what it means for you, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

_____________________________________________________________________________

For more detail about FTC regulations for health claims, see this link.

https://www.ftc.gov/business-guidance/resources/health-products-compliance-guidance

_______________________________________________________________________

About The Author

For the past 35 years Dr. Chaney and his wife Suzanne have been helping people improve their health holistically through a combination of good diet, exercise, weight control and appropriate supplementation.

Do Produce Prescriptions Improve Health?

October 3, 2023 by Dr. Steve Chaney

What Are The Pros And Cons Of Produce Prescriptions?

Author: Dr. Stephen Chaney

Can you imagine a world in which doctors asked their patients how many fruits and vegetables they were eating rather than how many drugs they were taking? Can you imagine a world in which doctors advised their patients to try a healthier diet before they put them on drugs?

Unfortunately, that world doesn’t exist currently and is unlikely to exist in the foreseeable future.

But what if there were another approach to encourage healthier eating? And what if it made a meaningful impact on people’s health?

There is such an approach, and it’s called a “produce prescription”.

“What are produce prescriptions?”, you might ask. Simply put, produce prescriptions are government programs that provide lower-income Americans with food insecurity extra income that can only be spent on fresh fruits and vegetables.

And it isn’t a lot of extra income. Previous studies have shown that lower-income Americans only need an extra $63 to $78/month to afford the recommended 3-5 servings of fresh fruits and vegetables a day.

But do produce prescriptions work? Do they significantly improve the diet and health of lower-income Americans who participate in programs offering produce prescriptions?

These are the questions that the authors of the current study (K Hager et al, Circulation: Cardiovascular Quality And Outcomes; 16:e009520, 2023) set out to answer.

How Was The Study Done?

The authors evaluated the results from 9 pilot produce prescription studies that were administered at 22 sites in 12 states between 2014 and 2020. These pilot studies were generally funded as experimental programs through Medicare and SNAP.

The pilot programs enrolled:

Adults at risk for poor cardiometabolic health (at risk for both heart disease and diabetes). The enrollment criteria included being overweight or obese and having either diabetes or elevated blood pressure.

Children who were overweight or obese.

People recruited from health centers serving predominantly low-income neighborhoods who were food insecure.

The authors of the study only included pilot studies that collected data on food intake and measured at least 1 biomarker of improved health (BMI (a measure of obesity), HbA1c (a measure of blood sugar control) and blood pressure).

The income incentive to purchase more fruits and vegetables varied from state to state but averaged $63/month.

With these criteria the study included 1817 children and 2064 adults.

The adults:

Averaged 54.4 years old.
Were 70.7% female, 29.8% non-Hispanic White, 45.1% non-Hispanic Black, 21.4% Hispanic, 3.6% other.

The children:

Averaged 9.2 years old.
Were 51.4% female, 9.2% non-Hispanic White, 13.1% non-Hispanic Black, 75.5% Hispanic, 2.3% other.

Overall:

3% of families enrolled in the program experienced food insecurity.
7% of families enrolled in the program were involved in SNAP.

Finally, the programs lasted an average of 6 months.

Do Produce Prescriptions Improve Health?

The results were encouraging:

At the beginning of the study fruit and vegetable intake was 2.7 cups/day for adults and 3.4 cups/day for children.

By the end of the study fruit and vegetable intake increased by 0.85 cups/day for adults and 0.26 cups/day for children.

Note: It is unfortunate that the authors chose to report fruit and vegetable consumption as cups/day because most of us think in terms of servings per day and the relationship between servings and cups varies with each fruit and vegetable. For example, one cup represents:

One serving of raw spinach.
Two servings of cooked spinach.
Two servings of most fruits.
One serving of bananas.

I could go on, but you get the point.

So, perhaps a better way to think about these results would be to say both adults and children in these low-income households were eating around 3.6 cups/day of fruit and vegetable intake – a 31% increase for adults and a 7.6% increase for children.

Another way of thinking about it would be to say that produce prescription programs got both adults and children in food-insecure households up to a healthier 3.6 cups/day of fruits and vegetables.

As for other outcomes:

Food insecurity dropped by one third for families participating in these programs.

The families reported that they felt healthier.

BMI (a measure of overweight and obesity) decreased for both adults and children.

HbA1c (a measure of blood sugar control) and blood pressure decreased in adults with cardiometabolic disease (heart disease and diabetes) at the beginning of the programs.

In the words of the authors, “In this large, multisite evaluation, produce prescriptions were associated with significant improvements in fruit and vegetable intake, food security, and health status for adults and children, and clinically relevant improvements in glycated hemoglobin (HbA1c), blood pressure, and BMI for adults with poor cardiometabolic health.”

What Are The Pros And Cons Of Produce Prescriptions?

The pros are obvious.

Food insecurity in low-income neighborhoods is a major problem. In the words of the authors:

“Food insecurity is strongly associated with poor health outcomes and higher health care costs.

Food-insecure individuals under use medications and choose cheaper, unhealthful foods due to costs.

[There are] stark disparities in household food insecurity…by race/ethnicity, with 7.1% of White, non-Hispanic households experiencing food insecurity compared with 21.7% of Black, non-Hispanic households, and 17.2% of Hispanic households.”

The authors do not claim that food insecurity is the only cause of health disparities in this country, but a simple program that reduces food insecurity and improves health outcomes is an obvious plus.

But there are cons as well.

While the results of these programs were statistically and clinically significant, they were relatively modest. In the words of the authors, “Produce prescriptions may need to be of longer duration or combined with additional components…”

Most Americans have the income to buy more fruits and vegetables but chose not to. Programs like this can reduce health disparities but are unlikely to improve the health of the American population as a whole.

There was no mention of the cost of implementing this program nationwide in the article, but that is likely to be a major stumbling block.

Unfortunately, government agencies never think of replacing old programs that don’t work with new programs that do work. They only think of adding the cost of the new program to their current budget.

Unfortunately, once you start talking about programs that increase government spending, they become political footballs. Because of this many beneficial programs end up in the dustbin of history.

The Bottom Line

Food insecurity among low-income households is a major cause of health disparities in this country. Several states across the country have piloted an idea called produce prescription programs. Simply put, these programs provide high-risk families who have food insecurity and poor health with a monthly stipend that can only be used to purchase fresh fruits and vegetables from grocery stores and farmers markets.

A recent study evaluated the effectiveness of these pilot programs and found the produce prescription programs:

Improved fruit and vegetable intake for the families who participated in the programs.

In addition:

Food insecurity dropped by one third for families participating in these programs.

The families reported that they felt healthier.

BMI (a measure of overweight and obesity) decreased for both adults and children.

HbA1c (a measure of blood sugar control) and blood pressure decreased in adults with cardiometabolic disease (heart disease and diabetes) at the beginning of the programs.

For more information on this study and a summary of the pros and cons of produce prescription programs, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease.

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