HCG diet works on a hypothesis that, in a situation of calorie deficit HCG primes the hypothalamus to signal the mobilization of body fat stores and hence use the stored fat as primary fuel for energy. In this way it may help in attaining the weight loss in overweight individuals.

HCG (Human Chorionic Gonadotropin) is FDA approved to treat many various health issues and has been in existence to do so for over 45 years by the medical community. It is considered safe and has few side effects. HCG is used to cause ovulation and to treat infertility in women, and to increase sperm count in men. HCG is also used in young boys with long, slender hands, large breasts, wide hips, buttocks and thighs with striation, knock-knees and underdeveloped genitals, often with undescended testicles. This can be caused by a pituitary gland disorder.

HCG has been used off label in the U.S. for weight loss since the 1970s when it was introduced from Europe. The doses used for weight loss are miniscule compared to doses used for the other conditions. After its initial introduction into the U.S., there were many HCG Diets that were spin-offs of the original HCG Diet program by Simeon. Many were done incorrectly and there were studies that said the program was no better than dieting alone.

Although there are studies to demonstrate significant weight loss and thousands of case reports regarding weight loss, body contouring and HCG, the FDA's position is that is must still be evaluated for weight loss. From our observations, there is no doubt in our minds that the HCG helps people lose weight through a very low calorie diet, and allows them to feel good, have energy, and decrease their appetite while they do it. This scenario, versus a scenario of a VLCD without HCG that results in conservation mode, is the basis for advocating this diet protocol.