What happens to fat and calories once they enter your body?

Most calories that a person consumes are used by the body as forms of energy or to help the body regulate functions, such as heat control (so that the body does not freeze or overheat, despite the temperature in the air or surrounding around it). If they fat and calories are not used, a small portion are stored in your body (like in the liver) to be used during in-active stages, like sleep. The rest are stored in cells. Excess calories and fat that can no longer fill the existing cells that the body has will end up being stored in newly created fat cells around the body.