You inherited a body type, a predetermined number of fat cells, a metabolic rate and body chemistry just as you inherited your eye color and hair color. Ectomorphs are the lean, lanky types. They are usually very thin and bony, with fast metabolisms and extremely low body fat. An ectomorph can eat like a horse without gaining an ounce. They are lean, muscular and naturally athletic.
Mesomorphs lose fat and gain muscle with ease.
They have slow metabolisms, they are often carbohydrate sensitive, they gain fat quickly if they eat poorly or don't exercise, and they lose fat slowly - even on a healthy diet. The tendency of endomorphs to store fat easily can be partly attributed to metabolic problems. For example, endomorphs often metabolize carbohydrates inefficiently. Endomorphs produce too much insulin when they eat carbohydrates and this leads to increased fat storage and difficulty in losing existing fat. Researchers at Johns Hopkins recently announced the discovery a compound called C75, that blocks an appetite-regulating hormone in the hypothalamus.