HCG dieters can fall into some traps along the way if they're not careful. One such trap would be not taking the HCG diet drops as specified. Another would be not consuming enough water. A third would be, for lack of a better term, cheating, but the fourth is to give into common human temptation and substitute one food for another despite what the diet specifies, for instance eating a fruit instead of a vegetable. You might do this rationalizing that "Hey, both have the same number of calories, so why not?"
Calorie counting, however, is not all that's behind the Official HCG Diet Plan as formulated by Dr. A.T.W. Simeons. Built into the diet is a natural balance of foods that, coupled with the ingestion of Human Chorionic Gonadotropin (HCG) hormone, instructs your body to burn calories from unwanted and unneeded fat areas rather than from fat that has been stored by your body specifically for times of hunger as a source of energy.
Thus one little substitution not only can retard the body's process of burning unwanted fat but also can lead to hunger pangs, which might then lead you into the worst pitfall of all, which is outright cheating -- that is, going back to your old eating habits.
The wrong types of calories and proteins should not be eaten. For instance, the main source of proteins should be fish, chicken and lean choices of meat. High-fat-content meats should be avoided at all costs.
When you keep everything in the proper balance, as envisioned by Dr. Simeons, you will stay healthier, burn "bad" fat more quickly, and exude more energy. Your metabolism will be keyed up by the proper diet coupled with the HCG diet drops, and the fat will melt away. This is the feature that other diets cannot duplicate or boast about, so please don't let yourself fall into the trap of substituting foods. Your body needs that nutritional balance -- and the HCG diet drops.