Mild hunger is common in the first few days, but this will pass by the second week, when even very small servings will be completely satisfying. This is due in part to your hypothalamus adjusting your metabolic rate, but more importantly to the amount of calories circulating in your system as a result of fat release. After that, many HCG dieters even feel as if they are stuffing themselves in order to reach the 1000-calorie limit!