Extreme diets with low calories aren't the best idea for everyone, but for the very obese, it's often the only choice besides surgery. The best way to do a very low calorie diet is under doctor supervision, but many people try to do it on their own. If you try a crash diet, only to return to unhealthy ways of eating after you lose weight, you are likely to regain the weight. For best results, use these extreme diets as a springboard to a healthier eating style--a way to break yourself of bad habits.

The Master Cleanse

The Master Cleanse, sometimes called the lemonade diet, was created by Stanley Buroughs in 1941. It involves eating no food. Instead, you drink a type of lemonade created from water, fresh squeezed lemons, maple syrup and cayenne pepper. You're additionally supposed to drink laxative tea and a warm salt water mixture in order to help you pass your bowels. The diet lasts from 10 to 30 days.

When coming off of the diet, be sure to ease your way back into eating. You don't want to start with a huge plate of spaghetti. Instead, spend the first day just drinking juice. This helps to get your digestive system active again. The following day, you can eat raw fruits and the next day include raw vegetables. From there, you should continue eating in a healthy manner and try to avoid junk foods.

Negative Calorie Diet

The negative calorie diet is based on the idea that certain foods burn more calories to digest than they actually contain. In theory, if you ate only foods that are like this, you will naturally lose weight, burning more calories than you are consuming. If you were to eat more food, you would burn more calories.

This theory has been proven to be true, but misleading. While there are some foods, such as celery, that burn more calories to digest than they actually contain, you'd have to eat a lot of celery to actually notice a difference on the scale. People following the negative calorie diet lose weight not because of the negative calorie effect, but because they are replacing unhealthy foods with fresh fruits and vegetables.

Very Low Calorie Diets

While the above diets are also very low in calories, a very low calorie diet, or VLCD, refers to a diet that you do only under the supervision of your doctor. It is a liquid diet that contains less than 800 calories per day. The drinks are made from a specially prepared powder that contains protein and other essential vitamins.

Doctors recommend this type of diet for patients that are very obese and who must lose weight quickly due to health problems. It is not for people who want to lose weight for cosmetic purposes. Talk to your doctor to see if this is an option for you.