One of the more popular bean soup diets is from Michael Greger, MD, author of "How Not to Die: Discover the Foods Scientifically Proven to Prevent and Reverse Disease." The diet encourages eating Dr. Greger's Champion Vegetable Bean Soup up to twice a day. In addition to the soup, you're allowed to consume any oil-free, plant-based foods, like whole grains, fruits, and vegetables. While there's no calorie restriction, the diet recommends limiting intake of calorie-dense foods like dried fruits and nuts for optimal weight loss results. Unlike other soup diets, Greger's is meant to be a lifelong shift to a plant-based diet. Proponents of this diet claim you can lose 9-16 pounds (4-7 kg) in just the first week.