Food: What the Heck Should I Eat?

by Mark Hyman, MD

Clock Icon 18 minute read


My guess is that you picked up this book because food confuses you. Why do I say that? Because I have been studying nutrition for 35 years, and even the experts are confused by the science. If the people we look to for nutritional guidance keep changing their views, it’s no wonder that the rest of us are befuddled and mystified.

When you wake up in the morning, do you wonder what you should eat that day? Are you sick of being mixed-up and confounded by conflicting media reports about the latest research on which foods are good or bad for us? One day eggs are unhealthy, and the next day they are a miracle food. One year the government tells us to eat six to eleven servings of carbohydrates (bread, rice, cereal, and pasta) as the foundation of our diet, and the next it tells us to cut carbs. The US Dietary Guidelines told us 35 years ago that all our health problems were derived from eating fat and recommended we eat fat “only sparingly.” Then, more than three decades later, they suddenly learned fat wasn’t so bad for us. We were just recently told, in the 2015 US Dietary Guidelines, “Uh, don’t worry about fat; there is no restriction on how much you can eat because the research shows no connection between obesity or heart disease and dietary fat. And that cholesterol we told you to avoid for fear of dropping dead of a heart attack? Well, we were wrong about that, too, so skip your egg whites and enjoy your whole eggs.”

Of course, the $1 trillion food industry provides us with all sorts of “healthy” options: low-fat, high-fiber, whole-grain, gluten-free—most of which are the opposite of healthy. My food rule is if there are health claims on the label, what’s inside is probably unhealthy. Multigrain Frosted Flakes, anyone?

All of this is enough to make you give up and just eat whatever you want, whenever you want, and in whatever quantities you want. It feels like nutrition whiplash.

This is the reason I have written this book. I want to help you undo all the beliefs about food that are making you fat and sick and replace them with a new understanding that will lead to health and longevity.

In the landscape of eating, there are many beliefs and dogmas, from vegan, Paleo, vegetarian, Mediterranean, and raw food, to ketogenic, high-fat, low-fat, omnivore. How can they all be right? There are benefits to each of these diets, but an all-in approach to one or another may not be the all-in answer.

Humans are adaptable. For generations we have consumed varied diets native to all sorts of environments from all over the planet, from arid desert landscapes to frozen Arctic tundra. So, should you be eating 80 percent carbs from mesquite, acorns, and wild plants, as the indigenous Pima of Arizona did for thousands of years, or 70 percent fat from whale blubber and seal, as the Inuit of the Arctic have traditionally eaten?

The good news is that science continues to refine and illuminate fundamental principles of good nutrition, and we know now more than ever what a good and healthy diet really looks like. I refer to these basic nutritional principles as the Pegan Diet, mostly as a spoof on the fanaticism of my Paleo and vegan friends, who often get hotheaded and emotional when defending their points of view. It’s sort of like the Hatfields and the McCoys.

The sad truth is that much of what we eat is not really food. At least, it has been so adulterated and processed we may as well not call it food. It is more of a food-like substance. And as a result, most of us are confused, baffled, and frustrated, not knowing whom to believe or what to eat.

I’ve also written Food because I believe that cultivating and consuming real, whole food is the answer to many of our world’s problems. How we grow it, produce it, and eat it affects almost every aspect of our lives and our society. Food is an honest how-to guide designed to answer the question, “What the heck should I eat?”

Now, you might be thinking, I know what food is. It’s the stuff you eat to provide fuel for your body so you can live. But it is so much more. It is medicine. It is information. Food literally controls almost every function of your body and mind. And it connects almost everything that matters in our lives. Food connects us to one another and to our bodies; it can reinvigorate our health, bring families together, restore vibrant communities, improve the economy and the environment, reduce pollution, and even help our kids get better grades and avoid eating disorders, obesity, and drug abuse; food can even reduce poverty, violence, homicide, and suicide. Our industrial food system drives many of these problems by enabling a national diet of sugary, starchy, overly processed, nutrient-depleted foods laden with pesticides, herbicides, hormones, antibiotics, and other harmful chemicals.

This book is meant to be a road map, based on the best and latest science of what to eat. What you put on your fork is the most important thing you do every day. It influences your capacity to live a rich, energetic, connected, soulful life—a life in which you have the energy to care for yourself, to love your friends and family, to help your neighbor, to fully show up for your work in the world, and to live your dreams. If you enjoy real, whole, fresh foods that you cook using real ingredients, you are positively affecting everything around you.

Simply put: Food is the doorway to living well and loving well—and to fixing much of what’s wrong with our world.


Each chapter in Part II of this book examines a different food group (meat, dairy, grains, vegetables, fruits, etc.) and aims to provide a full view of it, starting from the science and shifting to the experts—what they got right and what they got wrong. Each of these chapters contains a guide for how to integrate environmental and ethical guidelines into your shopping practices, as well as lists of what to eat and what not to eat—because, after all, isn’t that what we all really want to know? No part of this book involves deprivation and suffering. I want you to wake up every morning feeling good, enjoying life, and ready to eat great food. I think you’ll find that this book is not so much about what you can’t eat as it is about what you can—delicious, whole foods full of flavor, texture, and culinary surprises.

In Parts III and IV, I will show you how to use food as medicine to reset your body and to eat in a way that promotes health, and I’ll introduce you to simple guidelines and nutritional principles that synthesize the research on food, health, and disease and the environment. These guidelines are flexible and allow for a varied diet that is inclusive, not exclusive.

You will also learn which nutritional supplements are essential for health and healing. According to government data, 90 percent of Americans are deficient in one or more nutrients. In a perfect world, none of us would need supplements; however, given modern-day stressors, the depleted nature of our soil, the fact that our food is transported over long distances and stored for periods of time, and our exposure to an increasing load of environmental toxins, we all need a basic daily supply of vitamins and minerals to tune up our biochemistry.

You may notice that some information appears in more than one chapter. I’ve repeated certain important facts because they apply to more than one food group, and I know that some readers will skip around the book rather than read from start to finish. Better to say something twice than have you miss it altogether.

Even though this book contains a great deal of scientific information about food, my hope is that it actually empowers you to simplify your life. Cooking and eating become infinitely easier when you leave all the artificial stuff behind and focus on real, whole foods. It’s easier to remember what’s what. Ask yourself, Did a human being make this or did nature? Nature made an avocado, but not a Twinkie. Any five-year-old would understand that. Now let’s bust all those harmful nutritional myths and learn to embrace delicious, yummy foods that you love and that love you back.


The science of nutrition is confusing. But it shouldn’t be. There’s nothing more natural, or fundamental, in our lives. The miracle we humans have always known is this: Food exists specifically to energize, heal, repair, and uplift us. Every bite you take is a powerful opportunity to create health or promote disease. When I say it’s miraculous, I’m talking about real food, the kind that comes from the earth and fuels and sustains us, not the industrialized, hyperprocessed, hyperpalatable junk that degrades us and makes us sick. Which kind will you allow into your body? The choice is yours to make. Now let’s dig into the real story about food, get clear about what the science shows and what it doesn’t, and learn how to eat well for life.

Before we dig in, let’s start off with a little pop quiz. Answer the following questions based on your current beliefs about food. The answers appear at the end of Part I. Don’t cheat!


True or False?

  1. Oatmeal is a healthy breakfast.
  2. You should avoid egg yolks because they raise your cholesterol and cause heart attacks.
  3. Orange juice is a great way to start the day.
  4. Red meat is unhealthy and causes cancer and heart disease.
  5. The best way to lose weight is to eat a low-fat diet.
  6. Gluten-free food is healthy.
  7. If you want to lose weight, you should eat less and exercise more.
  8. Dairy is nature’s perfect food; it is essential for kids to grow and build bones and can prevent fractures.
  9. You should avoid butter because it has too much saturated fat and causes heart disease.
  10. Vegetable oil is better for you than butter.

My guess is that most of you got most of the answers wrong. I certainly was taught that all these statements were true—and I believed it! But they are not true. Tragically, those myths contribute to our growing burden of obesity and chronic disease. The purpose of this book is to separate fact from fiction, to bust myths and tell the truth about what we know, what we don’t, and what we need to eat to thrive.

Starting at a young age, we are all taught that we should “love thy neighbor as thyself.” Yet many of us neglect ourselves by eating low-quality industrial food that robs our health, makes us heavy and sluggish, clouds our minds, and dampens our spirits. If we fed our neighbors like most of us feed ourselves, we would all be in big trouble.

Many of us focus primarily on work, hobbies, and friends and tend to ignore our basic needs for good food and regular fitness and deep relaxation and quality sleep. We don’t connect the dots between what’s on our plate and our mental, physical, emotional, and spiritual well-being. Food is not just calories; it’s medicine. And most of us don’t realize how quickly our health would bounce back if only we thought of it that way. The question, then, is, How do we eat to create abundance, health, joy, happiness, and energy every day? How do we eat to prevent and even reverse most illnesses?

Chronic disease affects half of all Americans—among the culprits are dementia, heart disease, diabetes, cancer, neurological problems, depression, attention deficit disorder, autoimmune disease, allergies, reflux, irritable bowel, thyroid disorders, hormonal and menstrual problems, and skin problems, including eczema, psoriasis, and acne. The costs are staggering. Medicaid and Medicare are the single biggest drain on our federal budget. Annual spending on health care in 2016 was $3.35 trillion, or $10,345 per person (nearly $1 in $5 of our entire economy). And 80 percent of that goes toward the ongoing treatment of chronic lifestyle diseases that are preventable and reversible.

We all know food can harm—that drinking soda and eating junk food is bad for us. But how many of us believe food can heal? How many of us believe that food can cure depression, diabetes, arthritis, autoimmune disease, headaches, fatigue, and insomnia? That it can prevent and reverse dementia and heart disease or a hundred other common diseases and symptoms?

This is the biggest scientific discovery since the germ theory of disease in the mid-1800s and the development of antibiotics in the 1920s: Food is medicine.

Food is the most powerful drug on the planet. It can improve the expression of thousands of genes, balance dozens of hormones, optimize tens of thousands of protein networks, reduce inflammation, and optimize your microbiome (gut flora) with every single bite. It can cure most chronic diseases; it works faster, better, and cheaper than any drug ever discovered; and the only side effects are good ones—prevention, reversal, and even treatment of disease, not to mention vibrant optimal health.

Yet, sadly, doctors learn almost nothing about nutrition in medical school. That is changing, as more and more physicians face the limitations of drugs and surgery when it comes to healing the lifestyle-related diseases that cause so much suffering today. As director of the Cleveland Clinic Center for Functional Medicine and The UltraWellness Center, and chairman of the board of the Institute for Functional Medicine, I am a strong advocate for practitioner education and clinical research to prove that the use of food as medicine is effective at treating chronic disease. I have treated more than 10,000 patients using food as my main “drug,” and its benefits far exceed those of any prescription I have written. These cutting-edge centers have created programs that rely on functional medicine. Instead of labeling and treating diseases based on their symptoms, functional medicine addresses the root causes of disease. And when it comes to chronic illnesses, the culprit is nearly always food. Don’t get me wrong: We still treat patients holistically using advanced testing, carefully selected combinations of supplements and medications, and other lifestyle tweaks to create balance and healing. But our main “drug” is food. It’s that powerful when applied correctly. Functional medicine is the best model we have for addressing our chronic illness epidemic. It is the medicine of why, not the medicine of what. It is about why you have the disease, not just naming what disease you have. It strives to treat the underlying cause of the disease, rather than merely suppressing its symptoms.


Most Americans don’t eat food anymore. They eat factory-made, industrially produced food-like substances, or Frankenfoods, that contain trans fats, high-fructose corn syrup, monosodium glutamate (MSG), artificial sweeteners and colors, additives, preservatives, pesticides, antibiotics, new-to-nature proteins, and heightened allergens caused by genetic breeding and engineering. We call these anti-nutrients. If someone were to hand you a plain box of food with only a nutrition label and ingredients list on the outside, you would have a hard time guessing what it is—you couldn’t tell if it was a Pop-Tart or a Pizza Stuffer. This should make us all stop and think.

For example—this “food” item has thirty-seven ingredients. Read them and then see if you can guess what it is:

Ingredients: Enriched Bleached Wheat Flour [Flour, Reduced Iron, B Vitamins (Niacin, Thiamine Mononitrate (B1), Riboflavin (B2), Folic Acid)], Corn Syrup, Sugar, High Fructose Corn Syrup, Water, Partially Hydrogenated Vegetable and/or Animal Shortening (Soybean, Cottonseed and/or Canola Oil, Beef Fat), Whole Eggs, Dextrose. Contains 2% or Less of: Modified Corn Starch, Glucose, Leavenings (Sodium Acid Pyrophosphate, Baking Soda, Monocalcium Phosphate), Sweet Dairy Whey, Soy Protein Isolate, Calcium and Sodium Caseinate, Salt, Mono and Diglycerides, Polysorbate 60, Soy Lecithin, Soy Flour, Cornstarch, Cellulose Gum, Sodium Stearoyl Lactylate, Natural and Artificial Flavors, Sorbic Acid (to Retain Freshness), Yellow 5, Red 40.

Of course you can’t tell, because it is not real food. It is a food-like substance. In fact, it is Twinkies.

Should we really be putting this in our bodies?

Now let’s look at another example—see if you can guess what this is:

Ingredients: Organic Hearts of Romaine Lettuce

Pretty obvious, right? An avocado doesn’t have an ingredients list or a nutrition facts label. Neither does a steak. They are just food.

The food industry has invited itself into our homes and encouraged us to “outsource” our food and cooking. They got us out of the kitchen altogether. We have raised at least two generations of children who don’t know how to cook a meal from scratch using real ingredients and who spend more time watching cooking on television than actually cooking. Today’s industrial food-like substances have hijacked our taste buds and brain chemistry. Sugar is highly biologically addictive. And not by accident. Food giants have taste institutes, where they hire “craving experts” to identify the “bliss points” of foods to create “heavy users.” (These are terms companies use internally to describe what they do.) A top executive at Pepsi told me how excited he was that they had learned how to grow and harvest human taste buds in the lab. It would allow them to easily road test their new products and create even more addictive drinks or junk food. Our industrial food system, sponsored and supported by our government policies, has taken over our bodies, minds, and souls. It’s like the invasion of the body snatchers. Most of us have no clue. And worse, most of us blame ourselves for our bad habits, cravings, and weight gain.

Health is the most basic human right and it has been taken from us.


I have been writing about, lecturing on, and using food as medicine for a long time, and I’ve seen the health benefits in thousands of my patients. But it wasn’t until I participated in the movie Fed Up that I took a step back and realized just how bad the epidemic of industrialized food has gotten in our country. The film exposes how the sugar industry drives our obesity epidemic, and I was asked to go to South Carolina to talk to a low-income family about their health. I looked at this family’s health crisis, tried to understand the root causes, and worked to help them pull out of their scary downward spiral. Three of the five were morbidly obese, two had pre-diabetes, and the father had type 2 diabetes and kidney failure and was on dialysis. The family survived on disability and food stamps (or SNAP—the Supplemental Nutrition Assistance Program). They were under financial stress and felt hopeless. This vicious cycle of poverty and poor health affects more than 150 million Americans (including tens of millions of children) who are in some way struggling with the physical, social, and financial burden of obesity, chronic disease, and their complications.

And so it was with this family. The mother, father, and sixteen-year-old son were all morbidly obese. The teenager had 47 percent overall body fat, and his belly was 58 percent fat. To provide some perspective, the normal range for total body fat for a man is 10 to 20 percent. He said he was worried he would soon be 100 percent body fat. His insulin levels were sky-high, which drove a relentless cycle of sugar cravings and food addiction, leading to the storage of more and more belly fat. Obese at sixteen, he had a life expectancy thirteen years shorter than those of kids with healthy body fat, and he was twice as likely to die by the age of fifty-five as were his healthier friends. His father, at age forty-two, had renal failure from complications of obesity. The whole family was at risk.

They desperately wanted to find a way out but didn’t have the knowledge or the skills to escape the hold industrialized food had on them. They blamed themselves, but it was clear they were not at fault. They were victims.

When I asked them what motivated them to want to change, the tears began to flow. The father said he didn’t want to die and leave his wife and four sons. His youngest boy was only seven years old. The father needed a kidney transplant to save his life but wouldn’t be eligible until he lost forty pounds, and he had no clue how to lose the weight. None of the family members knew how to cook. They didn’t know how to navigate a grocery store, shop for real food, or read a label. They had no idea that the frozen chicken nuggets they were buying had 25 different ingredients and only one of them was “chicken.” They had been hoodwinked by the “health claims” on the packaged foods that were making them fat and sick—including “low-fat,” “diet,” “zero trans fats,” and “whole-grain.” Whole-grain Pop-Tarts? Cool Whip with zero trans fats?

Here’s a fun little fact about food labels, serving sizes, and marketing: In 2003, the food lobby coerced the Food and Drug Administration (FDA) into allowing food companies to label their products as trans-fat-free if the product had less than ½ gram of trans fats per serving. So, the makers of Cool Whip can state that it is a trans-fat-free “food” because there is less than ½ gram of trans fats in a 2 tablespoon serving, despite the fact that Cool Whip is mostly made up of trans fats. They can legally lie. Finally, in 2015, the FDA ruled that trans fats are not safe to eat, or non-GRAS (GRAS is an acronym for generally recognized as safe). But they’ve given the food industry a long time to get trans fats out of products. So beware. Read ingredients lists and don’t eat anything with the word “hydrogenated” on the label.

The parents in this South Carolina family grew up in homes where practically everything they ate was either fried or came from a box or can. They made only two vegetables—boiled cabbage and canned green beans. They didn’t have basic cooking tools, such as proper cutting boards to chop vegetables or trim meat. They had some old, dull knives that were hidden in the back of the cupboard and never used. Everything they ate was premade in a factory. They lived on food stamps and disability payments, spending about $1,000 a month on food, half of which went toward dining out at fast-food restaurants—that was their main family activity! They were trapped in a food desert and a cycle of food addiction. The conversation has changed now that science has proven that processed foods—and especially sugar—are addictive. When your brain is hooked on drugs, willpower and personal responsibility don’t stand a chance. But there is a way to break the cycle with real whole food.


I realized that the worst thing I could do to this family was to shame or judge them, prescribe them more medication, or tell them to eat less and exercise more (a subtle way of blaming them). Instead, I wanted to teach them to cook real food from scratch and show them they could eat well on a tight budget and feel satisfied.

When I looked through their fridge that first day, I was surprised to see a bunch of fresh asparagus. The mother explained that she used to hate them. “Once I had asparagus out of a can; it was nasty,” she said. “But then a friend told me to try one off the grill, and even though I didn’t want to, I tried it and it was good.” My theory about vegetables is this: If you hate them, then you most likely never had them prepared properly. They were canned, overcooked, boiled, deep-fried, or otherwise highly processed and tasteless mush. Just think of overcooked Brussels sprouts or tasteless canned peas. The worst!

So we got the whole family washing, peeling, chopping, cutting, touching, and cooking real food—whole foods like carrots, onions, sweet potatoes, cucumbers, tomatoes, salad greens, and even asparagus. I showed them how to peel the garlic, cut the onions, and snap the asparagus to get rid of the chewy ends. I taught them how to sauté the asparagus with garlic in olive oil, how to roast sweet potatoes with fennel and olive oil, and how to make turkey chili from scratch. We all cooked together. The family even made fresh salad dressing from olive oil, vinegar, mustard, salt, and pepper, instead of dousing their greens in the bottled dressings laden with high-fructose corn syrup, refined oils, and MSG that they once favored.

The youngest boys came running into the kitchen, lured away from their gaming consoles by the sweet, warm smells of chili and roasting sweet potatoes, fragrances that had never wafted out of their kitchen before. We all sat down at their table to eat the freshly prepared food, and they were surprised at how delicious and filling it was.

After a happy, healing meal of real food, cooked in less time and for less money than it would have taken them to drive to Denny’s and order deep-fried chicken nuggets, biscuits, gravy, and canned green beans, the nearly “superobese” son turned to me in disbelief and asked, “Dr. Hyman, do you eat real food like this with your family every night?” I said, “Yes, we do.” This child had been struggling with getting healthy, hoped to go to medical school, and wanted to help his family. I think it became clear that if this family were to simply choose real food, cooked at home—even on a budget—they would be on the right path to achieving these dreams and so much more.

When it came time to head home, I left amid tears of relief and of hope for a different future for this family. I gave them my Blood Sugar Solution Cookbook and a pocket guide called Good Food on a Tight Budget from an organization I work with called the Environmental Working Group. Five days after I left, the mother texted me to say that the family had already lost eighteen pounds collectively, and they were making turkey chili again. When I checked in nine months later, the family had lost 200 pounds collectively. The mother had lost one hundred pounds. The father had lost forty-five and was able to get a new kidney. The son had lost fifty pounds but had gone to work at a fast-food place and gained it back. However, he is back on track—and he went from a high of 338 pounds to 210 pounds—a 128-pound weight loss. And now he is applying to medical school!

If a family living in one of the worst food deserts in America and surviving on food stamps and disability income can do this, then any family can.


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