It is suspected that people who crave carbohydrates have lower serotonin levels, which increases cravings for carbohydrate-rich foods. As serotonin levels increase, the cravings decrease. Endorphins may also play a role in our need for carbohydrates. Sugar affects the release of these powerful chemicals, which ease stress and discomfort. Sarah Leibowitz, Ph.D., a professor of neurobiology at Rockefeller University in New York City, suspects that endorphins imbalances underlie obesity and eating disorders.
Obese people seem to be more sensitive to endorphins' appetite-stimulating effects than lean people.
Sugar and Hypoglycemia Sugar and other carbohydrate foods stimulate the insulin response so that glucose, the end result of sugar and carbohydrate metabolism, can be transported from the blood to every cell in the body. Insulin lowers the blood sugar level and this drop in blood sugar eventually triggers hunger. An unbalanced diet that is high in simple sugars and low in protein may cause a roller coaster effect on blood sugar levels, increasing the need to nibble on convenient foods, usually carbohydrates. An abnormal response to sugar intake is hyperinsulinemia, commonly referred to as hypoglycemia. The person's blood sugar level plunges below normal and he or she feels light-headed, dizzy and sweaty, and may even pass out.