Many people simply think that by barely eating at all then they will lose the weight that they want. This may work for a little while, but this is not a sustainable lifestyle to follow. Starving yourself actually does more harm than good to your body.
Your body burns a certain amount of calories while it is resting called your resting metabolic rate. Your body needs calories to burn during your resting periods. If your body doesn't have those calories to burn then it looks to your glucose stores. Once your glucose storage is used up your body doesn't turn to fat to burn next it turns to your muscles.
Only once your body has used up the muscle and then the carbohydrates will it move onto fat. If your body moves onto fat at this point then it is trying to make your nervous system surviving. Basically, starving yourself is a disastrous situation for losing weight.
If you do use this method of barely eating anything you are actually working against yourself when it comes to your metabolism. Your resting metabolic rate will slow down because your body thinks it needs to store more calories because it's in a starving state. Your resting metabolic rate can drop as much as 10%.
Those muscles that you have also contribute to your metabolism burning calories quicker. The more muscle you have the more calories you burn everyday from your resting metabolic rate. It takes more calories for your body to maintain and build that muscle. So if you starve yourself then your body uses it's muscle as fuel and your resting metabolic rate will slow down and you will reverse any weight loss you had. You are putting your body in a state to pack on more fat to keep itself alive.
What's worse about starving yourself is that at some point you have to start eating again. Once you do then you are just going to gain all of that weight back and potentially even more. Many people want to lose weight quickly and that is why they will result to starving themselves. Weight loss takes time and patience. You aren't going to lose 25 pounds in a month. If you do then you are doing something very wrong! A healthy weight loss per month is around eight pounds, two pounds per week.