no no no! sorry truckerman, but i have to disagree.
if you fast too often you can do more damage than good. do not attempt serious exercise when you are fasting- that is for when you are eating, and it will help your metabolism. you do not have the energy reserve to exercise and fast at the same time.
also DO NOT CUT DOWN ON SLEEP. this is one of the worst things you can do. your body needs the rest to reset everything- specifically your hormonal balances, and cutting down on sleep will disturb this process- consequently making weight loss more difficult!
fasting simply for weight loss is a bad idea. don't get me wrong- it is an effective tool, but only a tool, and the main emphasis should be on being well. this affects your brain chemistry to a healthier place, rather than being obsessive about the number on your scale.
please reevaluate everything you are doing (especially when not fasting) because i guarantee there is something there to change to help your weight loss, rather than continuing to fast and exercise while fasting.