It all depends on your metabolism.
The results can vary by a lot.
If you are used to eating heavy foods, and then suddenly switch to these diets, your metabolism (which has gotten used to the heavy food) will burn up all the fat in the same manner as it did before, but now with a lot less to burn off, and thus, you will lose more weight.
One thing about these crazy diets though: After you lose the weight, your metabolism will re-adjust to your new diet. So once you start eating normally again, you will gain weight as your metabolism will now be used to burning off less fat.
This is why it is highly recommended to keep a balanced diet, and exercise weight off. It will stay off too, and it is much more healthy for you.