Fad Diets are the diets that promise quick weight loss and usually require you to eat specific types of food. The weight that you lose is usually water and/or lean muscle rather than body fat. Some of these diets can be harmful to your health. They sometimes do not include exercise which is important for healthy living. They limit your food choices and usually keep you from a balanced diet Examples of fad diets: Fit for Life (food combining diet); Metabolife 356 (diet pills); Slim Fast (liquid diet) etc.