The Pritikin diet is a very-low-fat eating plan developed by Nathan Pritikin in the 1970s, originally for reversing heart disease, later popularised for weight loss. It restricts fat to about 10 percent of calories, eliminates added oils, butter, and fatty meats, and builds meals around whole grains, vegetables, fruit, and legumes, with small amounts of lean animal protein permitted. Followers are advised to eat high-bulk, low-energy-density foods until satisfied, using volume rather than willpower against hunger. Trials show it lowers cholesterol and blood pressure and produces weight loss, though critics note the restrictiveness, risks of essential fatty acid and fat-soluble vitamin shortfalls, and poor long-term adherence. As a supervised therapeutic programme with exercise, it has genuine evidence; as a self-directed slimming diet, its severity defeats most people.