As a gastroenterologist, Will Bulsiewicz, MD, sees patients with gut health issues that run the gamut, ranging from people who find themselves heading to the restroom not enough—or the opposite, way too often. Despite the wide range of probs, his solution almost always comes back to one major nutrient: fiber. In fact, Dr. Bulsiewicz preaches the importance of fiber so often to his patients that he’s writing a book on it, Fiber Fueled, so even more people can get schooled on its role.