Also, muscle mass is used for energy on a diet. The less muscle and the more fat is on your body, the lower is your metabolism and caloric needs. The result - you need less calories to maintain your weight, and you gain weight twice as quickly. Diets are negative, restricting, and depriving. You always crave and overeat those foods you restrict.
Diets are limited in essential nutrients and certain food groups.
Diets create a negative self-image. Remember - you are not a failure, the diet is a failure . As you can see, people who diet often can lower their metabolisms enough to decrease their caloric needs. The body will cut back its caloric needs to survive. Therefore, you won't lose more in the long run on a 500-calorie diet than you would on one above 1000 calories.