When individuals go on these crash diets, they are motivated initially due to the rapid weight loss that occurs. Although weight loss does occur, water weight is lost through the reduced glycogen stores and not the fat loss that individuals often strive for.
[2] In order to lose 1 pound of fat, a caloric deficit of 3500 kcals has to be made. Eventually the ability to rapidly lose weight diminishes due to numerous factors. A vicious circle often exists for dieters who go on these crash diets. It is often known as
yo-yo dieting, which is the repeated loss and regain of body weight due to dieting.
[2] Diets often cause caloric deficits, resulting in weight loss in the initial start of the program due to the use of glycogen, protein, and fat stores. However, eventually
metabolism begins to slow down to preserve the energy stores that are left in the body. This is caused by the numerous factors, such as the
hypothalamus detecting changes in fat stores and thus lowering metabolism to replenish the fat lost.
[10] As
lean body mass is also broken down to supply protein, the loss of muscle mass further accelerates the decline in metabolism, as muscles are energy utilizing organs. Eventually the individual reaches a weight loss plateau, loses motivation as rapid weight loss is no longer occurring, and thus returns to their normal eating habits.
[11] As normal dietary habits are resumed, the weight that was lost is often regained quickly, and even more. As the caloric intake increases along with
carbohydrate consumption, glycogen stores become replenished and thus the water weight. Since the basal metabolic rate is now lower than the rate at the initial start of the diet in the individual, further weight gain occurs as the body is "less efficient" than it was before in burning calories. Studies have proven that weight is readily regained at a much faster rate than it was lost. With the rapid regain in weight, eventually the dieter may find a new crash diet to try or a new gain in confidence, thus resulting in the vicious circle seen below. With repeated bouts of starvation, it results in faster and more significant lowering of the basal metabolic rate, and thus weight being regained faster.
[12]
Crash diets are low caloric diets that often include some gimmick to attract consumers that desire a "quick fix" solution.
[13] Along with the vicious circle that is seen, crash diets can have negative implications for one's health, especially if carried over the long term due to the avoidance and elimination of
food groups.
[1] Depending on the diet, negative health effects can include
malnutrition,
electrolyte imbalances, and increased susceptibility to chronic conditions such as
osteoporosis. Side effects include
nausea,
diarrhea,
lethargy, headaches,
dehydration, and much more.
[13]