Your body's fuel storage system.

The billions of cells in your body need a constant supply of fuel for energy, growth, and repair-when while you're sleeping This fuel comes from the foods you eat. But if your cells got their fuel only when you were eating, you'd have to eat all the time. Fortunately, your cells are able to store fuel and use it later.

The food that you eat is slowly broken down by your digestive system. When its broken down into its smallest chemical parts, these nutrients (NEW-tree-unts) are absorbed through the lining of your small intestine. From here, they travel through your bloodstream to all the cells in your body.

Only about half of the food you eat during a meal is used for fuel right away. The unused fuel is taken to special storage cells called adipose (AD-uh-pose) cells, or fat cells. Adipose cells are located all over your body, but most are located just under your skin. When your body needs more fuel, the adipose cells release stored nutrients into the bloodstream.

Eating too much food causes your body to store more fat than it needs. Not eating enough food doesn't allow your body to store the fuel it will need later. Without these stored nutrients, the body starts to break down muscle tissue for fuel.

Your body needs fuel to keep your heart beating, your lungs breathing, and your mind thinking. And because your body is also growing and developing, its especially important to give it the right amount and type of fuel. Eating a variety of foods and not overeating high fat or junk,, foods will help you (and all your billions of cells) stay healthy!