A diet designed to produce a dramatic decrease in body weight in a short time. Losses may be as high as 3 kg (more than 6 lb) in the first 3 days, but much of this loss is water rather than fat. This is because water is associated with carbohydrate stored in the body as glycogen. Crash diets are usually high in protein and low in carbohydrate, resulting in a reduction of glycogen and its associated water. The weight lost due to water losses is regained when the dieter returns to a balanced diet with normal levels of carbohydrate.
Some crash diets do result in reduced body fat, but usually lean tissue is also lost. It can be dangerous to lose lean tissue from vital organs. When the dieter returns to a normal calorific intake, weight is more likely to be regained as fatty tissue than as lean tissue. Fatty tissue has a lower metabolic rate, consuming less calories, so that the dieter is likely to gain more weight than before the diet started. See also Yo-Yo diet.
Subjects: Medicine and Health.