There are two types of anorexia. In the restricting type of anorexia, weight loss is achieved by restricting calories (following drastic diets, fasting, and exercising to excess).
Treatment of anorexia involves restoring a healthy weight, treating the underlying psychological problems, and addressing behaviors that promote the problem. One thing is certain about anorexia. Severe calorie restriction has dire physical effects.
When your body doesn’t get the fuel it needs to function normally, it goes into starvation mode and slows down to conserve energy.