Mark Hyman is an American physician, scholar, and New York Times bestselling author. He is the founder of the UltraWellness Center, a columnist for The Huffington Post, and a regular contributor to the Katie Couric Show. He has authored several books, including Eat Fat, Get Thin, and Ultrametabolism, so it’s no surprise his followers have paid great attention to his advice on diets and healthy eating. Hyman is a supporter of functional medicine.