The Pegan Diet by Dr. Mark Hyman

Dr. Mark Hyman shares an excerpt of his new book, “The Pegan Diet,” which combines elements of paleo and veganism to reduce inflammation and balance blood sugar

No matter what questions we have about health and wellness, Dr. Mark Hyman always seems to have the answer. That’s why when we found out that he was publishing a new book, called The Pegan Diet, we couldn’t contain our excitement to dive in. Over the course of the next month, Katie will be “eating Pegan,” and we encourage you to join her! To help you get started, Dr. Hyman has shared an excerpt of his book. If you want to join us in eating Pegan with Katie, Dr. Hyman, and team KCM, then make sure to follow along on our KCM instagram page for all of our updates, and to share your own progress!



Plant and animal foods have a wide array of molecules that influence every aspect of our biology: proteins; fats; carbohydrates; vitamins; minerals; soluble, insoluble, and resistant fibers; prebiotics; probiotics; anti- oxidants; phytochemicals; and even microRNA, the genetic material of plants, which we absorb and which communicates with our own DNA. Foods are made not of ingredients but of complex compounds, all dynamically influencing your biology. Think about the implications of every single bite of food you eat. You are literally programming your biological soft- ware for better or worse. Most don’t understand the link between what they eat and how they feel, or between food and the myriad ailments to which humans are prone. This lack of understanding has resulted in a growing dependence on doctors, prescriptions, and ultimately hospitals to rescue them from damaging food choices. If you learn to view food as instructions that influence every aspect of your biology, and learn to combine that knowledge with the joy of cooking, there will be only pleasure and healing.

Functional medicine, the science of creating health, focuses on the root cause of disease, and food almost always plays a role in both the cause and the cure. If a doctor sees a patient complaining of hopelessness, sad- ness, trouble sleeping, low sex drive, and lack of appetite, the doctor will diagnose depression. But “depression” is just the name we give to people who share those symptoms. It says nothing about the causes of the symptoms, which could be many. The treatment prescribed is an antidepressant, but depression is not a Prozac deficiency. In conventional medicine, thinking stops at the diagnosis. In functional medicine, think- ing starts at the diagnosis. Depression, for example, may be caused by low thyroid function, celiac disease, B12 deficiency, vitamin D deficiency, antibiotics that alter the microbiome, heavy metal toxicity, omega-3 deficiency, or even insulin resistance (from too much starch and sugar). Each of these causes requires a very different treatment.

In functional medicine, we don’t divide the body into separate organs; we look at the functioning of seven different systems. Nearly every one of the 155,000 diseases listed in the disease classification system known as ICD-10 is caused by imbalances in these seven interconnected systems. Fix those systems and you fix the problem. How do you do that? You start with food. You can eat to reverse deficiencies. You can eat to heal your gut, reduce inflammation, enhance your immune function, balance your hor- mones, and boost your detoxification system. You can eat to strengthen your bones and your muscles.

In Principle 1, I’m going to give you an overview of each of the seven systems in functional medicine and how you can use food as medicine, or as I like to say, your farmacy.


Your gut microbiome, the magical kingdom of microbes living in you, may be the most important organ in your body. An unhealthy microbiome can cause heart disease, cancer, diabetes, obesity, autism, autoimmunity, dementia, allergies, asthma, fibromyalgia, Parkinson’s, and skin disorders like acne, eczema, and psoriasis, not to mention all the digestive disorders, including irritable bowel, reflux, and colitis.1 Bad bugs in our gut grow for two reasons: not eating enough of the foods that feed the good guys, and eating too many gut-busting foods. The biggest culprit when it comes to harming the gut is gluten. Modern wheat has an excess of powerful inflammatory proteins called gliadins that create a leaky gut, driving inflammation and imbalances in the gut flora. Leaky gut is also called increased intestinal permeability. The surface area of your intestinal lining is the size of a tennis court. And it is only one cell thick— one cell between you and a sewer! The glue that holds all the intestinal cells breaks down, creating little holes that allow food proteins and bacterial products to “leak” into the bloodstream and interact with the immune system (60 percent of which is right below the intestinal lining). This causes inflammation in every system of the body. Sugar, excessive starch, processed foods, and refined vegetable oils also feed the bad bugs and lead to leaky gut and inflammation throughout the body, causing many chronic diseases. Sugar, starch, and bad fats. These are what America and most of the world eats. They’re about 60 percent of our calories.

Is there a gut-healing diet? Absolutely. First, good bugs need all types of fiber to thrive. The most essen- tial fibers are called prebiotics. Certain foods have high levels, including artichokes, asparagus, plan- tains, seaweed, and more. All fiber-rich foods will help keep your inner garden healthy— vegetables, fruits, nuts, seeds, whole grains, and beans.

In addition to fiber, probiotics are critical for healthy gut function. You might take a probiotic sup- plement, but you can get probiotics from fermented foods like sauerkraut, pickles, tempeh, miso, natto, and kimchi.

Your gut also needs specific nutrients to function well. Zinc, in foods like pumpkin seeds and oysters, is necessary for digestive enzyme function. Omega-3 fats from fish, such as sardines and herring, are needed to regulate inflammation and heal leaky gut. Vitamin A, from sources like beef liver, cod liver, salmon, and goat cheese, is also necessary for gut healing and regulating gut immune function. Foods with collagen, such as bone broth, contain glycosami‑ noglycans, which help heal the gut. Kudzu, a Japanese root, is a powerful gut-soothing food.

In Principle 15, I’ll share new research about the role of polyphenols in gut health and how to start a gut-healing protocol. Food is the most important regulator of your microbiome. If you feed your gut well, you’ll set yourself up for optimal health.


Every level of your health is impacted by what you eat. You can eat to build muscle, build healthy bones, gain energy, balance your hormones, fix your gut, boost your immunity, improve heart health, and everything in between. Next time you chomp down on something, ask yourself if you are fine with it becoming part of you for the long term. If not, don’t eat it and seek out the best-quality ingredients instead (and by the way, taste and quality go together). Everything (our health, our communities, our planet) is connected to what we eat (or don’t). As we move through the rest of the principles of the Pegan Diet, infused with the science of functional medicine, you’ll learn practical ways to use food as your farmacy.

This excerpt is from Dr. Mark Hyman’s new book, The Pegan Diet