A lack of food can cause the body to go into starvation mode over time. Starvation mode is a metabolic response to the body being deprived of food. Not eating enough can slow the body’s metabolism, making it harder to lose weight. The body can detect when there’s been a shift in calorie levels and reacts accordingly. With severe food restriction, the body begins to conserve its fuel, stored fat. The result is that you burn less calories. Fortunately, the hcg diet keeps your body out of “starvation mode.”