A 24-year-old girl who had not eaten for nearly 15 days and weighed only 50.24 kilograms died. Scientists found that in the natural state, human weight will tend to maintain a stable range.

Weight also has a fixed "tuning point" to regulate hunger and metabolism. Scientists have found that changes in gut bacteria also play a pivotal role in the pathogenesis of obesity.. That is, when you eat something that is likely to be fat, you are more likely to get fat.