Insulin resistance
Weight gain is the primary effect of diet-induced obesity, but there are a variety of additional physiological side effects. One such side effect is that the body gains more fat cells. The increased number of fat cells persists even after the diet becomes lower in fat. Weight put on during the high-fat diet also tends to persist. Changes in the composition of the body are accompanied by hormonal changes. High levels of leptin and insulin are produced; at the same time, the body becomes resistant to both. Insulin resistance in particular is fed by the addition of more fat cells.