Dieting is the practice of eating food in a regulated and supervised fashion to decrease, maintain, or increase body weight. In other words, it is conscious control or restriction of the diet. A restricted diet is often used by those who are overweight or obese, sometimes in combination with physical exercise, to reduce body weight. Some people follow a diet to gain weight (usually in the form of muscle). Diets can also be used to maintain a stable body weight and improve health. In particular, diets can be designed to prevent or treat diabetes.