you can't just starve yourself to lose weight. you have to eat the right stuff. you have to eat enough and be active. if you get the right nutrients count calories is done this way:
-determine how many calories you have to eat a break even. that is not to gain or not to lose weight. This is done for you in MFP.
- then eat the the right foods, but calories just below that amount to create a deficit. eating fewer calories than you actually burn. I cannot stress enough that you balance your nutrients and stay away from junk for the most part.
- don't eat a whole lot less. eating less than 1200 ( not really I magic number. some need more and some need less) calories for most people will cause them to go into starvation mode. your energy is zapped and you start getting fat without eating much.
if you found yourself in starvation mode, get professional help. they can help you calculate the calories you need to kick start and get out of it.
recovering starvation mode is scary because you have to actually gain weight first. that's because you have to kick start your metabolism and your body has to adjust. I mean you eat at a rate that would keep you at a deficit normally and you would lose weight. but for a time you will gain weight. 4 weeks of rapid weight gain scares most people to death but sometimes it's required in order to get your system back on track. mamy people give up and stay in the vicious circle.