Human Chorionic Gonadotropin, or hCG is a hormone produced during pregnancy by the placenta to that redirects calories from the mother to the fetus. During pregnancy, hCG controls metabolic functions and helps break down fat for use as energy. Your hypothalamus is a part of your brain that also regulates hormone function, creating a "set-point" for your metabolism, as well as regulating appetite. HCG, used in conjunction with a very low calorie diet, can help to fool your hypothalamus into using stored fat for energy, producing weight loss.
Stick to the diet protocol. You'll eat only 500 calories daily -- but not just any 500 calories will work. You'll need to eat exactly the foods that are called for. Breakfast should be as much coffee or tea as you'd like, with no added sugar, although stevia is acceptable. Lunch and dinner are the same -- your choice of a piece of fruit, one piece of melba toast, one serving of a steamed green vegetable such as spinach, asparagus or fennel, and 100 g of a lean protein with all visible fat removed. You can eat your fruit between meals as a snack if you care to; but no substitutions may be made.
Have an hCG injection every day for at least 23 days, but no more than 40 days. The amount of hCG hormone used in the diet protocol is significantly less than a woman's body naturally produces during pregnancy, but still powerful enough to suppress your appetite so you don't feel hungry and signal your hypothalamus to maintain your metabolism by releasing stored fat for calories. Normally, a very low calorie diet would slow your metabolism, making weight loss difficult. Proponents of the diet claim that hCG prevents your body from losing lean muscle mass and maintains your basal metabolic rate.
Take a 6-week break from the hCG diet and then begin another round of hCG injections. After 40 days on protocol, your hypothalamus actually resets itself -- but only for a short period of time, from a few days to a few weeks. You'll need to start another round of the diet to continue to see results. The six-week break between hormone injections prevents your body from becoming immune to the effects of hCG.