This is because the body has learned that worse times can also come. What would normally be burned is now stored as extra fat. The result is that people gain weight again. And this weight could well be more than the weight before starting the crash diet. No yo-yo effect Those who want to lose weight well will therefore have to lose weight slowly. Let the body notice that there is no food shortage. Eat at least 1300 calories a day. Do not lose more than 500 grams per week and build muscle. Make sure that you do not lose too much weight and that you also change your lifestyle permanently.