Dr. Mark Hyman — who's pictured above — has long been a leading voice in the field of “functional medicine”, first as founder and director of The UltraWellness Center, and later as Director of the Cleveland Clinic Center for Functional Medicine.

He's an eleven-time New York Times best-selling author and has been a regular guest on The Dr. Oz Show, CBS This Morning, Today, Good Morning America, The View, and CNN.

As Dr. Hyman says, “Food is the most powerful medicine available to heal chronic disease, which accounts for over 40 million deaths a year and will cost the US $95 trillion over the next 35 years.”

Dr. Hyman's new book, “Food: What the Heck Should I Cook?” follows his previous volume, “Food: What the Heck Should I Eat?” and is intended to help people follow the “Pegan” diet he devised and advocates.

The book provides more than 100 recipes, some of which were contributed by Dr. Hyman’s friends and colleagues, including Chef José Andres, Dave Asprey (Bulletproof.com), Mark Bittman, Hugh Jackman, Dr. Mehmet Oz, Gwyneth Paltrow, Dr. Drew Ramsey, and Dr. David Perlmutter.

Let’s delve into his new book and then scrutinize the Pegan diet that it seems designed to help readers start and follow.

Our review of “Food: What the Heck Should I Cook?”
There’s a great deal to like about Dr. Hyman’s new book, which is divided into three parts:

Part I provides general principles and the 10 pillars of the Pegan diet, and ends with a section called “Recipe-Free Cooking”, which, as he says, is designed to help readers “… compose a snack or meal without having to plan ahead or even follow directions because you understand the way different flavors and textures work together.”

To that end, Part I provides “templates” for three go-to meals, called “Berry Anything Smoothie”, Quick and Easy Super Salad”, and Kitchen Sink Stir-Fry”.

Part II of the book is titled “Creating a Conscious Kitchen”, and in it, Dr. Hyman offers good guidance on these topics:

  • Choosing the right foods
  • Third-party labels and certifications
  • Pantry staples & perishables
  • Condiments, salt, spices, and herbs
  • Eat the rainbow (he urges eating a wide variety of fruits and vegetables and identifies, by color, which types of fruits and vegetables feature certain antioxidants and nutrients)
  • Cooking with the right fats
  • Cooking techniques (which methods are healthiest, and a guide to vegetable cooking techniques)
  • Essential gadgets and tools

Part III contains the 100-plus recipes he either created or that were contributed by friends and colleagues. Wisely, his book includes a “Nutritional Analysis Index” to let readers know what they’re getting from each recipe.

(The tasty recipe titled Coriander Salmon with Coconut-Tomato Salsa, which Dr. Hyman kindly allowed us to republish, is featured in “Food: What the Heck Should I Cook?”.)

Finally, the Resources section includes “Clean Seafood”, which lists four websites where you can find healthful, sustainably produced seafood. One of those websites is the Marine Stewardship Council (msc.org), where Vital Choice is listed as source of MSC-certified sustainable seafood.

Although Dr. Hyman doesn’t include their website, the non-profit organization Fish Choice lists Vital Choice as a supplier of certified-sustainable seafood, and reveals which of our seafood species are independently certified sustainable, and by which organization.

The pros and cons of Dr. Hyman’s Pegan diet plan
The evidence is clear that a diet based on whole foods is far preferable to one — like the standard American diet — based on processed and fast foods. But beyond that, there’s a great deal of disagreement.

In  “Food: What the Heck Should I Cook?”, Dr. Hyman describes how he arrived at the “Pegan” label for his dietary philosophy: “While sitting on a panel at a medical conference, discussing the importance and discrepancies of modern nutrition, I found myself between one doctor who was a strict vegan and another who was passionately Paleo. When it was my turn to talk, I joked that the best description of my dietary beliefs must be ‘Pegan’ — and the Pegan Diet was born.”

The principles of the Pegan Diet resemble those of the Mediterranean Diet and anti-inflammatory eating plans like Dr. Andrew Weil's, which focus on whole, unprocessed foods, emphasize plant foods, favor cultured foods (e.g., yogurt and fermented vegetables), and limit meats, dairy, and starchy foods. (You'll see a graphic depiction of the "Pegan diet pyramid" at the end of this article.)

In fact — with the notable exception of his advice to avoid grains and strictly limited dairy (especially low-fat dairy) — the principles of the Pegan Diet aren't wildly different from the “conventional” advice found in the current 2015-2020 Dietary Guidelines for Americans, which recommend a diet “… higher in vegetables, fruits, whole grains, low- or nonfat dairy, seafood, legumes, and nuts; moderate in alcohol (among adults); lower in red and processed meat; and low in sugar-sweetened foods and drinks, and refined grains.”

All in all, Dr. Hyman’s Pegan diet plan is a worthy, generally evidence-based approach to healthy, sustainable eating. And his new book is a clear, concise guide to starting and enjoying a Pegan diet.

That said, Dr. Hyman’s plan includes elements that seem faddish, echoing as they do the themes of best-selling books whose core assertions aren’t backed by persuasive evidence — as we’ll detail below.

These are the 10 principles of Dr. Hyman’s Pegan diet, summarized from the description in  “Food: What the Heck Should I Cook?”:

  1. Plants should be the star of your diet — As Dr. Hyman says, “… 75% of your plate should be filled with veggies at every meal, the more diverse the better”.
  2. Quality counts, in more ways than one — He advises us to avoid pesticides, antibiotics, hormones, GMOs, additives, preservatives, dyes, artificial sweeteners, and synthetic or highly processed food ingredients.
  3. Go gluten-free or gluten-light and avoid or limit most dairy — This restriction implies that gluten is inherently unhealthful. That’s certainly true for people with celiac disease, or who are gluten-sensitive, but there isn’t good evidence that gluten is inherently unhealthful.
    • Instead, there's ample evidence that — in moderation — whole grains with or without gluten are actively healthful, thanks to their abundance of fiber, antioxidants, and micronutrients (“whole-grain” baked goods don’t always deliver the same benefits) . See Whole Grains May Help Deflect Diabetes, Do Whole Grains Hurt or Help Gut Health?, Gluten Often Plays the Gut-Health Patsy, and their links to related articles.
    • As to dairy, Dr. Hyman notes that some 75% of people are lactose intolerant, although that genetic trait is concentrated in Asian and other ethnic groups and less common in people of primarily European ancestry.
    • And although he says dairy (i.e., cow’s milk) naturally contains dozens of hormones that can cause cancer and weight gain, there’s substantial evidence that dairy — especially fermented dairy foods like cheese and yogurt — can be actively healthful when consumed in moderation. For more on this topic, see Can Dairy Foods Help Heart & Metabolic Health? and its links to related articles.
    • Dr. Hyman also says that low-fat dairy foods are less healthful than whole dairy foods, and we agree that there’s substantial evidence for that; see Full-Fat Dairy – Especially Yogurt – May Deter Diabetes.
  4. Limit gluten-free grains, too — Dr. Hyman believes that most whole grains should be avoided because they can raise blood sugar, and he advises eating only small amounts of low-glycemic options such as black rice, millet, quinoa, teff, buckwheat, and amaranth. Although his preference for low-glycemic options makes sense, his concern about other whole grains doesn't really fit the evidence: again, see Whole Grains May Help Deflect Diabetes.
  5. Avoid sugar and eat fruit in moderation — Dr. Hyman believes that diets should be low in anything that might spike blood sugar and increase insulin production, because these processes are linked to inflammation, obesity, diabetes, Alzheimer’s, cancer, heart disease, stroke, infertility, and more. The evidence supports his disdain for added sugars (see Big Sugar Paid Scientists to Pin Heart Disease on Saturated Fats), but there isn't good evidence to back avoidance of fruits. Certainly, people with diabetes or insulin resistance should limit their intake of sugary fruits, but that's a special case. There's even evidence that antioxidant-rich fruits help prevent spikes in blood sugar: see Berries Fight Sugar Spikes and Berries Seen to Balance Blood Sugar
  6. Eat clean meat, poultry, and whole eggs — Dr. Hyman notes that the alleged links between meat and cardiovascular disease, cancer, and diabetes haven’t withstood scrutiny. He does advise avoiding factory farmed meats, which are often produced with hormones or antibiotics. Likewise, he notes that eggs have been absolved of blame for cardiovascular disease, and advises looking for eggs from pasture-raised hens, which are richer in nutrients.
  7. Choose low-mercury, sustainably harvested fish — He endorses low-mercury, sustainably harvested fish — specifically, the species he calls SMASH fish: wild-caught salmon, mackerel, anchovies, sardines, and herring — for their omega-3 fatty acids and other healthful nutrients.
  8. Eat lots of healthy fats — Dr. Hyman advises people to favor omega-3 fats from seafood, nuts, and seeds, monounsaturated fats from olive oil and avocados, and saturated fats from coconut oil, coconut butter, whole eggs, sustainably raised or grass-fed meats, and grass-fed butter or ghee.
  9. Vegetable oils are not a health food — As readers of Vital Choices know, we agree with Dr. Hyman that it’s wise to avoid oils high in omega-6 fatty acids, including sunflower, corn, grape seed, safflower, peanut, sunflower, palm, soybean, and cottonseed. Oddly, he includes canola oil in his list, even though it’s quite low in omega-6 fatty acids, possibly because most canola oil comes from GMO seeds. However, canola oil possesses one of the healthiest fatty acid profiles, and it’s not hard to find organic, non-GMO canola oil. In addition, “high-oleic” sunflower oil, which is not hard to find, is extremely low in omega-6 fatty acids.
  10. Enjoy legumes once in a while — Dr. Hyman is wary of eating lots of beans because, as he writes, “The lectins and phytates they contain may hinder mineral absorption, cause inflammation, and even exacerbate 'leaky gut' and autoimmune disease.” However, he does endorse occasional enjoyment (no more than ½ cup daily) of lentils, peas, black beans, garbanzo beans, adzuki beans, and green beans, due to their relatively lower starch content.
    • We’re frankly puzzled by Dr. Hyman’s position on beans, because it’s undermined by overwhelming evidence to the contrary. The benefits of their “resistant” starch are well documented: see A Paleo-Diet Rule Meets Resistance and its links to related articles. In fact, the American Diabetes Association ranks beans as the number one anti-diabetes “superfood”.
    • The pillar of Dr. Steven Gundry’s bestseller, “The Plant Paradox”, is his claim that lectin-type proteins — which are found in almost every plant food — are an unrecognized source of health problems, including leaky gut, chronic inflammation and autoimmune disease. However, the studies Dr. Gundry cites to support his claims either don’t support them or have nothing to do with them, nor do the available biomedical studies support his claims.
    • Dr. Hyman's concerns about the phytates in beans — which have much less than other common plant foods such as dark leafy greens — seem unwarranted. See the "Paleo-advocates’ reasons for banning beans don’t add up" section of A Paleo-Diet Rule Meets Resistance.
    • Beans play important roles in the Mediterranean diet, predominate in the diets of many people who live in so-called “blue zones” (where lifespans far exceed the world average), and overwhelming evidence links beans to better weight control and reduced risks for cardiovascular disease and cancer. Their prominent role in clearly healthful diets likely flows from the fact that beans are high-fiber, antioxidant-rich, nutrient-rich sources of protein, whose resistant starch helps prevent diabetes.

Pyramid depicting the priorities of Dr. Hyman's Pegan diet