It is common for mild hunger during the first few days. However, this will pass by the first or second week. You will find even very tiny servings to be completely satisfying. This is partly due to your hypothalamus adjusting your metabolic rate but largely due to the amount of calories circulating in your system from the fat being released. It is common that HCG dieters feel as though they are stuffing themselves in order to reach that 500-calorie limit.