The amount of weight that a person can lose by not eating depends on their current weight and body chemistry.
The weight lost by not eating would be short-lived, unhealthy and may result in weight gain.
A common belief is that if a person would skip meals and not eat at all, they would lose more weight than by eating healthy and exercising. While this may be true in the short term, in the long run, they would end up gaining weight, according to WebMD expert Kathleen M. Zelman MPH, RD, LD.
This is because the body enters starvation mode and tries to conserve the calories and nutrients that it does have. Because of this, a person may end up gaining weight from skipping meals, rather than losing weight as intended. It's best to eat a balanced diet and exercise on a regular basis in order to lose weight.