Medically supervised very low calorie diet (800 calories). ok to exercise. principle of ketosis. burn about 400 cal/day/hr monitor. safe?

No safe shortcuts: This type of diet often makes the body angry, decreasing calories too much too quickly will send your body into starvation mode. Less calories = weight loss, but your body will become more efficient at holding onto calories, so you will gain the weight back and then some later on. Weight watchers is the safest and most consistent in my experience with thousands of people.