All parts of our bodies require energy- our brains, stomach, muscles, etc. Even when we are sleeping, our bodies require energy! Cells in your body get energy from the foods that are eaten, such as glucose (a sugar). This food is ingested via consumption and digested via the digestive system. Food is initially mechanically digested in the mouth. The stomach, intestines and other parts of the digestive system then chemically digest the food. Eventually, through diffusion, the glucose and other nutrients are delivered to the mitochondria of your cells. Here, the glucose is converted into energy via the process known as cellular respiration. Cellular respiration converts glucose and oxygen into water, carbon dioxide and usable form of energy called ATP (this stands for adenosine triphosphate).