What Is The Pegan Diet?

Written by Dr. Steve Chaney on . Posted in Pegan Diet

Is The Pegan Diet Healthy?

Author: Dr. Stephen Chaney


pegan diet newsJust when you thought you had heard about every possible diet, along comes a new one called the Pegan diet. What is the Pegan Diet and is it healthy?

The Pegan diet was introduced by Dr. Mark Hyman in his new book, “Food: What the Heck Should I Eat?”. I don’t agree with Dr. Hyman on everything (which will become apparent when I review his diet), but I hold him in high regard. He is much more credible than most of the doctors who are writing popular blogs and diet books.

Basically, the Pegan diet is a combination of the Paleo and Vegan diets (hence the name). It
was meant to combine the best features of each while eliminating their drawbacks.


What Are The Pros & Cons Of The Vegan And Paleo Diets?


pegan diet fruits and vegetablesPros And Cons Of The Vegan Diet:

Dr. Hyman listed the following pros:

  • The diet ideally incorporates mostly whole, plant-based foods.
  • It provides lots of vitamins (especially antioxidants and most of the B vitamins), fiber, and healthy fats (monounsaturated and polyunsaturated fats).
  • It avoids what he calls the “baggage that comes from feedlot meat”. He is, of course, referring to the inhumane way that most of the animals that end up on our plates are treated. It also avoids the saturated and trans fats associated with the meats most Americans prefer.

I would add that Vegan diets are very healthy. As I discuss in my book, “Slaying the Food
Myths” (https://slayingthefoodmyths.com). we know that people who consume whole food
Vegan diets over a period of many years weigh less and have lower incidence of heart
disease, diabetes, and cancer than the general population.

Dr. Hyman listed the following cons:

  • Vegan diets are likely to be deficient in vitamin B12, iron, zinc, copper, and vitamin D.
    Of these deficiencies, B12 is the most serious because B12 only comes from animal
  • Vegan diets will not provide enough of the heart healthy omega-3s, EPA and DHA.
    Again, that’s because these omega-3 fatty acids come primarily from animal sources.
  • Vegan diets may not provide enough protein, especially for seniors because they have
    increased protein requirements. It is possible to get enough protein from Vegan foods,
    but some diligence is required.
  • The food industry provides plenty of highly processed, junk food versions of “Vegan”
    foods. So, it is possible to be Vegan and eat an unhealthy diet.

I would concur and add that calcium is another likely deficiency for Vegans

Pros & Cons Of the Paleo Diet:

pegan diet meatDr. Hyman listed the following pros:

  • The Paleo diet eliminates most sugars and grains. That eliminates sodas, junk foods, and most processed foods, which is a very good thing.
  • It is a low-glycemic diet, which is helpful for people with diabetes. He went on to say that it could reverse type 2 diabetes.

I would concur and add that it has a healthier profile of fats than most low-carb diets.

However, I would also note that a low-carb version of the Mediterranean diet is also helpful for people with diabetes, and a whole food, very low-fat version of the Vegan diet has also been shown to reverse type 2 diabetes.

Dr. Hyman listed the following cons:

  • The Paleo diet is essentially a myth. There were many types of diets in prehistoric times.
  • Many people following the Paleo diet consume too much meat and too little plant-based foods.
  • Our prehistoric ancestors may have consumed as much as 100-150 grams of fiber a day. The average American consumes 8 -15 grams a day, and people on a Paleo diet may consume even less. (Note: The estimate of 100-150 grams of fiber per day is based on the same type of faulty evidence that lead to the Paleo diet in the first place. Our prehistoric ancestor’s fiber intake probably varied tremendously depending on their local food supply. However, it is safe to assume they ate much more fiber than we do.)

I would concur and add:

  • Studies have shown that women consuming the Paleo diet have low intakes of calcium, magnesium, iodine, thiamin, riboflavin, and folate.
  • The Paleo diet relies heavily on red meat, which an agency of the World Health Organization has classified as a probable carcinogen. Reliance on grass-fed beef in the Paleo diet does not reduce this concern.
  • There is no evidence that the Paleo diet is healthy long term. In fact, there is no evidence that any meat-based, low-carb diet is healthy long term.

For more about the pros and cons of the Vegan and Paleo diets – plus which diets I consider healthy – see my book “Slaying The Food Myths.

What Is The Pegan Diet?

In the words of Dr. Hyman: “…the best versions of both diets [Paleo and Vegan] are built on the same foundation: Eat real, whole food. Vegan and Paleo diets focus on foods that don’t raise our blood sugar, plenty of fresh vegetables and fruits, healthy protein and [healthy] fats, and no crap [junk foods].” Dr. Hyman started with that foundation for the Paleo diet.

Here are Dr. Hyman’s 12 characteristics of his Pegan diet with my comments:


#1. Stay away from sugar. My comment: He gets an A+ for this one because, unlike many of today’s diet gurus, he is not telling you to avoid all sugars. He is focusing on the sugars and refined carbohydrates that cause spikes in blood sugar and insulin levels. As I point out in my book, there is the same amount of sugar in an 8-oz soda and a medium apple. It’s the sodas, refined carbs, and sugary foods you want to avoid, not apples.

pegan diet plant-based#2: Eat mostly plants. My comment: Again, he gets an A+ for this one. He recommends covering half your plate with a variety of colorful fruits and vegetables.

#3. Easy on the fruits. My comment: This one is an A-. He is correct in pointing out that some fruits like grapes and melons are higher in sugar and/or lower in fiber than other fruits. He is missing the point that blood sugar response to foods is a very individual characteristic. Some people do well on most fruits. Other people need to be more careful about which fruits they eat.

#4: Stay away from pesticides, antibiotics, hormones, and GMO foods. My comment: Another A+, especially because he included artificial additives, preservatives, dyes, and sweeteners.

#5: Eat foods containing healthy fats. My comment: I give him a B- for this one. He is right on the mark when he talks about polyunsaturated omega-3 fats and the monounsaturated fats found in nuts, seeds, olive oil, and avocados as being healthy. He is a bit off-base when he starts talking about “healthy” saturated fats in grass-fed beef and butter. He also advocates coconut oil despite the fact there is no good long-term evidence coconut oil is healthy.

#6: Stay away from most vegetable, nut, and seed oils. My comment: He gets a C- for this one. These oils are a good source of omega-6 polyunsaturated fats, which are essential for the human body. There is nothing inherently unhealthy about them. However, I do agree with him that we consume way too much of these oils in relation to monounsaturated and omega-3 polyunsaturated oils. If he had said “reduce consumption of” rather than “stay away from” those oils, I would have upgraded him to an A-.

pegan diet dairy#7: Avoid or limit dairy. My comment: He gets a B for this one. The statement that dairy “doesn’t work for most people” is a myth. Avoiding or limiting dairy is excellent advice for anyone who is dairy-sensitive. I would also agree that we should not necessarily be aiming for 2 to 3 servings of dairy per day for everyone. However, dairy is a major source of calcium, magnesium, and vitamin D in the American diet. If dairy is to be eliminated or limited, consideration should be given to where people will get those important nutrients.

#8: Think of meat and animal products as condiments – not the main course. My comment: He gets an A+ for this one. As I say in my book, fruits and vegetables can neutralize many of the toxic effects of meats. One or two ounces of meat in a green salad or a stir fry is much healthier than a 6-ounce steak with fries.

#9: Eat sustainably raised or harvested low-mercury fish. My comment: He gets an A- for this one. I downgraded him because he ignored contamination of fish with PCBs and other industrial chemicals. Once you take that into account, most farm-raised and some sustainably harvested fish are eliminated from consideration.

#10. Avoid gluten. My comment: He gets a C- for this one. It is good advice if you are gluten sensitive. If you are not, gluten-containing foods are not generally a problem. The real focus should be on the blood sugar response to the food, not on whether the food contains wheat or another gluten-containing grain.

#11: Eat gluten-free whole grains sparingly. My comment: This one rates a D. Whole grains are a good source of some nutrients like vitamin E. They are also an excellent source of fiber. It is important to realize that there are many types of fiber and each plays a different role in intestinal health. The fibers found in whole grains are different than those found in fruits and vegetables. They are an important part of a healthy diet. Dr. Hyman states that whole grains also raise blood sugar. That is an overstatement. Their effect on blood sugar may not be zero, but it is less than that of refined grains. Moreover, when eaten as part of a healthy meal, their effect on blood sugar is minimal.

#12: Eat beans only once in a while. My comment: He gets a D- for this one. He has already limited meat to a condiment. If you are also only eating beans every once in a while, you will have trouble meeting your protein requirements, especially as you get older.

You will find more details about the science behind many of the comments I made above in my book, “Slaying The Food Myths.”


Is The Pegan Diet Healthy?

The simple answer is that no long-term studies have been done, so we have no evidence that the Pegan diet is either healthy or unhealthy. However, the Pegan diet incorporates many of the best features of the Vegan diet, and we know the Vegan diet is very healthy long term. We also know that a semi-vegetarian diet is almost as healthy as the Vegan diet, so incorporating small amounts of meat into the Pegan diet is unlikely to make it unhealthy. On the basis of those considerations, the Pegan diet would appear to be healthy.

However, we have 5 food groups for a reason. Any time you eliminate food groups you introduce potential nutritional deficiencies that can affect your health. That is why I have concerns about statements like “Stay away from most vegetable, nut, and seed oils”, “Avoid dairy”, “Eat…whole grains sparingly”, and “Eat beans only once in a while”. If you removed those limitations, the Pegan diet would likely be very healthy. However, as it is currently described, the Pegan diet has too many questionable restrictions to be considered as healthy.


The Bottom Line


Dr. Mark Hyman has combined the best features of the Paleo and Vegan diets to create a new diet, which he calls the Pegan diet.

I have analyzed the Pegan diet in great detail in the article above:

  • It has many characteristics of a healthy diet.
  • However, it also has several unwarranted dietary restrictions that are likely to create nutritional deficiencies which may have adverse health consequences.
  • There are no long-term studies to tell us whether the Pegan diet is healthy or unhealthy.

In summary, the diet has some good features and some bad features. Because it has both good and bad features, one cannot predict whether the diet will be healthy or unhealthy long term. Until there is long-term experimental evidence that it is healthy, I cannot recommend it.

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.

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Latest Article

A Low Carb Diet and Weight Loss

Posted January 15, 2019 by Dr. Steve Chaney

Do Low-Carb Diets Help Maintain Weight Loss?

Author: Dr. Stephen Chaney


low carb dietTraditional diets have been based on counting calories, but are all calories equal? Low-carb enthusiasts have long claimed that diets high in sugar and refined carbs cause obesity. Their hypothesis is based on the fact that high blood sugar levels cause a spike in insulin levels, and insulin promotes fat storage.

The problem is that there has been scant evidence to support that hypothesis. In fact, a recent meta-analysis of 32 published clinical studies (KD Hall and J Guo, Gastroenterology, 152: 1718-1727, 2017 ) concluded that low-fat diets resulted in a higher metabolic rate and greater fat loss than isocaloric low-carbohydrate diets.

However, low-carb enthusiasts persisted. They argued that the studies included in the meta-analysis were too short to adequately measure the metabolic effects of a low-carb diet. Recently, a study has been published in the British Medical Journal (CB Ebbeling et al, BMJ 2018, 363:k4583 ) that appears to vindicate their position.

Are low carb diets best for long term weight loss?

Low-carb enthusiasts claim the study conclusively shows that low-carb diets are best for losing weight and for keeping it off once you have lost it. They are saying that it is time to shift away from counting calories and from promoting low-fat diets and focus on low-carb diets instead if we wish to solve the obesity epidemic. In this article I will focus on three issues:

  • How good was the study?
  • What were its limitations?
  • Are the claims justified?


How Was The Study Designed?

low carb diet studyThe investigators started with 234 overweight adults (30% male, 78% white, average age 40, BMI 32) recruited from the campus of Framingham State University in Massachusetts. All participants were put on a diet that restricted calories to 60% of estimated needs for 10 weeks. The diet consisted of 45% of calories from carbohydrate, 30% from fat, and 25% from protein. [So much for the claim that the study showed low-carb diets were more effective for weight loss. The diet used for the weight loss portion of the diet was not low-carb.]

During the initial phase of the study 161 of the participants achieved 10% weight loss. These participants were randomly divided into 3 groups for the weight maintenance phase of the study.

  • The diet composition of the high-carb group was 60% carbohydrate, 20% fat, and 20% protein.
  • The diet composition of the moderate-carb group was 40% carbohydrate, 40% fat, and 20% protein.
  • The diet composition of the low-carb group was 20% carbohydrate, 60% fat, and 20% protein.

Other important characteristics of the study were:

  • The weight maintenance portion of the study lasted 5 months – much longer than any previous study.
  • All meals were designed by dietitians and prepared by a commercial food service. The meals were either served in a cafeteria or packaged to be taken home by the participants.
  • The caloric content of the meals was individually adjusted on a weekly basis so that weight was kept within a ± 4-pound range during the 5-month maintenance phase.
  • Sugar, saturated fat, and sodium were limited and kept relatively constant among the 3 diets.

120 participants made it through the 5-month maintenance phase.


Do Low-Carb Diets Help Maintain Weight Loss?

low carb diet maintain weight lossThe results were striking:

  • The low-carb group burned an additional 278 calories/day compared to the high-carb group and 131 calories/day more than the moderate-carbohydrate group.
  • These differences were even higher for those individuals with higher insulin secretion at the beginning of the maintenance phase of the study.
  • These differences lead the authors to hypothesize that low-carb diets might be more effective for weight maintenance than other diets.


What Are The Pros And Cons Of This Study?

low carb diet pros and consThis was a very well-done study. In fact, it is the most ambitious and well-controlled study of its kind. However, like any other clinical study, it has its limitations. It also needs to be repeated.

The pros of the study are obvious. It was a long study and the dietary intake of the participants was tightly controlled.

As for cons, here are the three limitations of the study listed by the authors:

#1: Potential Measurement Error: This section of the paper was a highly technical consideration of the method used to measure energy expenditure. Suffice it to say that the method they used to measure calories burned per day may overestimate calories burned in the low-carb group. That, of course, would invalidate the major findings of the study. It is unlikely, but it is why the study needs to be repeated using a different measure of energy expenditure.

#2: Compliance: Although the participants were provided with all their meals, there was no way of being sure they ate them. There was also no way of knowing whether they may have eaten other foods in addition to the food they were provided. Again, this is unlikely, but cannot be eliminated from consideration.

#3: Generalizability: This is simply an acknowledgement that the greatest strength of this study is also its greatest weakness. The authors acknowledged that their study was conducted in such a tightly controlled manner it is difficult to translate their findings to the real world. For example:

  • Sugar and saturated fat were restricted and were at very similar levels in all 3 diets. In the real world, people consuming a high-carb diet are likely to consume more sugar than people in the other diet groups. Similarly, people consuming the low-carb diet are likely to consume more saturated fat than people in the other diet groups.
  • Weight was kept constant in the weight maintenance phase by constantly adjusting caloric intake. Unfortunately, this seldom happens in the real world. Most people gain weight once they go off their diet – and this is just as true with low-carb diets as with other diets.
  • The participants had access to dietitian-designed prepared meals 3 times a day for 5 months. This almost never happens in the real world. The authors said “…these results [their data] must be reconciled with the long-term weight loss trials relying on nutrition education and behavioral counseling that find only a small advantage for low carbohydrate compared with low fat diets according to several recent meta-analyses.” [I would add that in the real world, people do not even have access to nutritional education and behavioral modification.]


low carb diet and youWhat Does This Study Mean For You?

  • This study shows that under very tightly controlled conditions (dietitian-prepared meals, sugar and saturated fat limited to healthy levels, calories continually adjusted so that weight remains constant) a low-carb diet burns more calories per day than a moderate-carb or high-carb diet. These findings show that it is theoretically possible to increase your metabolic weight and successfully maintain a healthy weight on a low-carb diet. These are the headlines you probably saw. However, a careful reading of the study provides a much more nuanced viewpoint. For example, the fact that the study conditions were so tightly controlled makes it difficult to translate these findings to the real world.
  • In fact, the authors of the study acknowledged that multiple clinical studies show this almost never happens in the real world. These studies show that most people regain the weight they have lost on low-carb diets. More importantly, the rate of weight regain is virtually identical on low-carb and low-fat diets. Consequently, the authors of the current study concluded “…translation [of their results to the real world] requires exploration in future mechanistic oriented research.” Simply put, the authors are saying that more research is needed to provide a mechanistic explanation for this discrepancy before one can make recommendations that are relevant to weight loss and weight maintenance in the real world.
  • The authors also discussed the results of their study in light of a recent, well-designed 12-month study (CD Gardener et al, JAMA, 319: 667-669, 2018 ) that showed no difference in weight change between a healthy low-fat versus a healthy low-carbohydrate diet. That study also reported that the results were unaffected by insulin secretion at baseline. The authors of the current study noted that “…[in the previous study] participants were instructed to minimize or eliminate refined grains and added sugars and maximize intake of vegetables. Probably for this reason, the reported glycemic load [effect of the diet on blood sugar levels] of the low-fat diet was very low…and similar to [the low-carb diet].” In short, the authors of the current study were acknowledging that diets which focus on healthy, plant-based carbohydrates and eliminate sugar, refined grains, and processed foods may be as effective as low-carb diets for helping maintain a healthy weight.
  • This would also be consistent with previous studies showing that primarily plant-based, low-carb diets are more effective at maintaining a healthy weight and better health outcomes long-term than the typical American version of the low-fat diet, which is high in sugar and refined grains. In contrast, meat-based, low-carb diets are no more effective than the American version of the low-fat diet at preventing weight gain and poor health outcomes. I have covered these studies in detail in my book “Slaying The Food Myths.”

Consequently, the lead author of the most recent study has said: “The findings [of this study] do not impugn whole fruits, beans and other unprocessed carbohydrates. Rather, the study suggests that reducing foods with added sugar, flour, and other refined carbohydrates could help people maintain weight loss….” This is something we all can agree on, but strangely this is not reflected in the headlines you may have seen in the media.

The Bottom Line


  • A recent study compared the calories burned per day on a low-carb, moderate-carb, and high-carb diet. The study concluded that the low-carb diet burned significantly more calories per day than the other two diets and might be suitable for long-term weight control. If confirmed by subsequent studies, this would be the first real evidence that low-carb diets are superior for maintaining a healthy weight.
  • However, the study has some major limitations. For example, it used a methodology that may overestimate the benefits of a low-carb diet, and it was performed under tightly controlled conditions that can never be duplicated in the real world. As acknowledged by the authors, this study is also contradicted by multiple previous studies. Further studies will be required to confirm the results of this study and show how it can be applied in the real world.
  • In addition, the kind of carbohydrate in the diet is every bit as important as the amount of carbohydrate. The authors acknowledge that the differences seen in their study apply mainly to carbohydrates from sugar, refined grains, and processed foods. They advocate diets with low glycemic load (small effects on blood sugar and insulin levels) and acknowledge this can also be achieved by incorporating low-glycemic load, plant-based carbohydrates into your diet. This is something we all can agree on, but strangely this is not reflected in the headlines you may have seen in the media.
  • Finally, clinical studies report averages, but none of us are average. When you examine the data from the current study, it is evident that some participants burned more calories per hour on the high-carb diet than other participants did on the low carb diet. That reinforces the observation that some people lose weight more effectively on low-carb diets while others lose weight more effectively on low-fat diets. If you are someone who does better on a low-carb diet, the best available evidence suggests you will have better long-term health outcomes on a primarily plant-based, low-carb diet such as the low-carb version of the Mediterranean diet.

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.