Mark Hyman is a physician and prominent advocate for functional medicine who writes extensively about nutrition, metabolic health, and chronic disease. His dietary philosophy centers on the idea of “food as medicine,” emphasizing nutrient-dense, whole, minimally processed foods.
Although Hyman is not as strictly low-carb as some of the other people in this collection, his approach has considerable overlap with low-carb eating: minimally processed foods, abundant non-starchy vegetables, quality protein, healthy fats, fiber, and individualized carbohydrate intake.
What I particularly like about Hyman's approach is that the emphasis isn't simply on what to avoid. It is also about choosing foods that provide good nutrition.
Dr. Mark Hyman's dietary philosophy begins with a simple idea: food isn't merely fuel—it can influence our health.
Hyman is a prominent advocate of functional medicine, an approach that emphasizes lifestyle and attempts to identify factors contributing to chronic disease.
He argues that a diet dominated by sugar, refined carbohydrates, and ultra-processed foods contributes to insulin resistance and poor metabolic health.
His alternative is a diet centered on nutrient-dense, minimally processed food.
Perhaps the simplest part of Hyman's advice is:
Eat food that looks like food.
Hyman distinguishes between:
• Refined/rapidly absorbed carbohydrates: sugar-sweetened drinks, sweets, white flour products, pastries, white rice, many processed snacks—foods he generally recommends avoiding or sharply limiting.
• “Smart” or slow carbohydrates: non-starchy vegetables, legumes, berries and other lower-sugar fruit, and—in people who tolerate them and have good metabolic control—some whole grains and starchy vegetables.
So the goal is to consume “smart carbohydrates,” not simply “low carbohydrates.” His standard view is to obtain carbohydrates from nutrient-dense, fiber-rich foods rather than eliminate them wholesale.
He discourages foods containing large amounts of added sugar, refined flour, and highly processed ingredients.
This is an area where Hyman's recommendations overlap considerably with Robert Lustig, Eric Westman, William Davis, and other people in this collection.
They don't prescribe identical diets, but they share a skepticism toward the modern diet dominated by refined and ultra-processed foods.
Blood-glucose regulation is central to Hyman’s approach. Glycemic load refers to how much a serving of food is likely to raise blood sugar, taking into account both how quickly its carbohydrates are digested and how much carbohydrate it contains.
Hyman recommends limiting sugar and rapidly digested starches, which can cause sharp rises in glucose and insulin, especially in people with insulin resistance. Instead, he emphasizes non-starchy vegetables, protein, healthy fats, nuts, and seeds.
For people with insulin resistance, type 2 diabetes, obesity, metabolic syndrome, or strong sugar cravings, he may recommend a temporary lower-carbohydrate diet. He also views ketogenic or very-low-carb diets as potentially useful therapeutic tools for selected metabolic problems rather than necessary lifelong diets.
Hyman also stresses nutrient density—choosing foods rich in vitamins, minerals, fiber, healthy fats, and phytonutrients while minimizing sugar, refined starches, and other empty calories.
Hyman rejects the old idea that dietary fat should automatically be minimized.
He recommends foods containing unsaturated fats, particularly:
Extra-virgin olive oil
Avocados
Nuts and seeds
Fatty fish
These foods are consistent with dietary patterns associated with good cardiovascular outcomes.
The health effects of saturated fat remain an area of disagreement between low-carb advocates and many cardiovascular organizations.
Protein is another important component of Hyman's approach.
Protein is essential for muscle repair, enzyme production, and immune function. Hyman recommends high-quality protein sources, including grass-fed meats, pasture-raised poultry, wild-caught fish, organic tofu, and legumes. Adequate protein intake is especially important for maintaining muscle mass and supporting metabolic health as we age..
He emphasizes food quality as well as quantity.
Although Hyman is sometimes associated with low-carbohydrate eating, he doesn't advocate an all-meat diet.
Quite the opposite.
While not vegetarian, Hyman’s diet places significant emphasis on plant-based foods. Vegetables and fruits provide a wealth of antioxidants, vitamins, and minerals that combat oxidative stress and reduce the risk of chronic diseases. He encourages eating a variety of colorful produce to maximize phytonutrient intake.
He advises people to “eat the rainbow”—choosing vegetables and fruits of different colors to obtain a variety of phytonutrients.
This emphasis on plants distinguishes his approach from some stricter ketogenic and carnivore diets.
Hyman has become increasingly interested in the intestinal microbiome—the enormous community of microorganisms living in our digestive system.
Diet strongly influences which organisms thrive there.
Fiber-rich plant foods provide substrates that gut bacteria can ferment, while fermented foods such as yogurt, kefir, sauerkraut, and kimchi can introduce or support beneficial microorganisms.
Scientists are still learning how changes in the microbiome translate into specific health outcomes.
But there is broad agreement that dietary diversity and fiber can contribute to a healthy gastrointestinal environment.
One of the strongest areas of agreement across modern nutrition research is the desirability of limiting ultra-processed foods.
These products often combine refined starches, added sugars, fats, salt, flavors, and other ingredients in forms that are easy to eat quickly and in large quantities.
Hyman argues that they should be replaced whenever practical with minimally processed foods.
This doesn't require perfection.
The objective is to make real food the default, rather than allowing packaged products to dominate the diet.
Hyman’s dietary philosophy is supported by a growing body of scientific evidence linking diet to chronic disease prevention and management. Studies have shown that diets high in processed foods and added sugars are associated with increased inflammation, obesity, and chronic conditions like diabetes, cardiovascular disease, and certain cancers. Conversely, nutrient-dense diets rich in whole foods have been shown to reduce inflammation, improve metabolic markers, and enhance longevity.
For instance, research on low-glycemic diets demonstrates their effectiveness in stabilizing blood sugar levels and reducing the risk of type 2 diabetes.
Transitioning to a healthier diet may seem daunting, but Hyman provides practical advice for making sustainable changes:
1. Start with Small Steps: Begin by incorporating more whole foods into your meals and gradually reducing processed and sugary items. For example, swap sugary breakfast cereals for oatmeal topped with fresh berries and nuts.
2. Plan and Prepare: Meal planning and preparation are key to maintaining a healthy diet. Set aside time each week to plan meals, shop for groceries, and prepare ingredients in advance. Having healthy options readily available reduces the temptation to reach for unhealthy snacks.
3. Read Labels: Learning to read food labels is crucial for avoiding hidden sugars, unhealthy fats, and artificial additives. Look for products with simple, recognizable ingredients and minimal added sugars. Products labeled “natural,” “low-fat,” “gluten-free,” or “keto” aren't automatically healthy.
4. Cook at Home: Cooking at home allows you to control the quality and quantity of ingredients in your meals. Experiment with new recipes and cooking techniques.
5. Stay Hydrated: Proper hydration is an often-overlooked aspect of a healthy diet. Drinking water throughout the day supports digestion, energy levels, and overall health. Herbal teas and infused water can add variety without added sugars.
6. Mindful Eating: Hyman emphasizes the importance of mindful eating—paying attention to fullness cues, savoring each bite, and avoiding distractions like screens during meals. Mindful eating promotes better digestion and helps prevent overeating.
Hyman's broader philosophy also emphasizes:
Regular physical activity
Strength training
Adequate sleep
Stress management
Social connection
Nutrition matters enormously, but it doesn't operate in isolation.
This is another reason I find the concept of metabolic health more useful than simply thinking about weight.
Functional medicine itself is controversial. Critics argue that some functional-medicine practitioners recommend extensive testing, supplements, or treatments that aren't always supported by strong clinical evidence. Hyman's individual claims and recommendations differ from mainstream medical practice.
But many of the central elements of his dietary advice—reducing added sugar and ultra-processed food, eating vegetables, obtaining adequate protein, choosing mostly whole foods, exercising, and getting sufficient sleep — are not controversial.
Dr. Hyman’s approach to a healthy diet underscores the transformative power of food in promoting health and preventing disease. By prioritizing nutrient-dense, whole foods and minimizing processed items, individuals can improve their physical and mental well-being.
His fundamental message is to improve the quality of the food we eat.
Eat real food. Eat plenty of vegetables. Get adequate protein. Include healthy fats. Reduce sugar, refined carbohydrates, and ultra-processed foods.
For someone interested in low-carb eating, I think Hyman provides a useful reminder:
A healthy diet isn't defined only by what you leave out. It also matters what you put in its place.