text: after a crash diet or fasting, do you gain all the weight back even if you try to eat healthy afterward? do you gain more weight back? yes, and more.  by crash dieting (using the definition of extreme caloric restrition) you have convinced your body that it needs to store any energy it consumes rather than use it to power the body.  in other words, you have told it to get fat.   that is why eating 6 small meals a day is the best for losing weight.  as an example, if you are a normal healthy adult female you need about 1200 cals a day on average to power your body.  so eat 6 small meals of 200 cals each (good cals, not candy bars!) with protien, dairy, fruits and nuts being your focus and you will lose weight (providing you burn 1200 cals!) because your body will see that you have enough food to survive and it does not need to store the energy rather than conserve it.