It only takes a small amount of HCG to capitalize on the metabolize function of the hormone for weight loss. This has to be done with a reduced calorie diet to allow the HCG to metabolize fat stored in the body instead of fat and calories consumed. HCG also occurs naturally when the body goes into starvation mode to help the body survive on a reduced caloric intake. The problem with the natural occurrences is that the body also conserved fat while in starvation mode. The result is a loss of energy and muscle. If the body is not in starvation mode, but has an excess of HCG it will make up caloric deficiencies with fat stored in the body without being concerned with conserving.
This is the main reason that just drastically reducing your calories would not produce a long term weight loss. Your body is going to give up the muscle, reduce your energy level and crave food to increase calories. This also does not help with sustaining the weight loss. Muscle to fat ratio is one of the factors in your metabolism. If you are reducing your calories drastically to lose weight without the support of an HCG type product you lose muscle and as you start increasing your calories you will not have the muscle to help your metabolism