Research shows people with too much fat produce too much Leptin. As fat metabolism increases more fat energy seeps into the blood stream. If the body is not creating demand through expenditure, resting blood glucose levels rise and to maintain safe levels, the glucose must be converted to glycerol strands that eventually create more adipose tissue...
In a nut shell, more Leptin makes fat energy available, and if expenditure doesn't equal the amount of energy seeping into the blood, the energy gets converted back into fat. This makes food intake needs drop, and when eating a normal diet, blood glucose levels elevate more then normal, and fat is created. It's a vicious cycle.
The protocol keeps Leptin levels stable as the very low calorie protocol creates demand for the fat. Because the specific amount of hCG stimulates Leptin, once again, normal food intake would predispose fat production (even though it doesn't make caloric sense).
The very low calorie protocol counters the elevated Leptin levels and the hCG keeps Leptin levels from declining. The protocol's rigidity and hCG's affect on Leptin creates a very controlled environment. Hormone fluctuations from menses, stress, and uncontrolled environments would increase as well as decrease Leptin levels on protocol. It's mind numbing how Dr. Simeons created, through deduction, this protocol. Years and years of observation without modern knowledge. AMAZING.