Like I mentioned in other thread, to starve yourself is not a
good and healthy way of dieting. Everytime you starve yourself,
your body remembers it so as soon as you start eating, your body
will try to absorb the food and store it as fats. In the end, you
might end up piling on more weight than you lost for the few
days.
If you want to do exercise to lose weight, just make sure you do
something you enjoy and sustainable. When you exercise your
metabolism increases, and hence can afford to eat more without
gaining weight (as long as food intake < energy burnt). However,
as soon as you stop exercising, your metabolism slows down and
you'll soon put on weight again.