Most people get their daily energy from carbohydrates. We gain a lot of carbohydrates from foods like cereals and potatoes. However, the food we eat must be broken down before the body can take advantage of it. When carbohydrates are broken down, they become sugars. The small intestine carries out most of the digestive processes by using enzymes that work together with enzymes produced in the liver and the pancreas. The enzymes help to break down the food into a form that can be used by our cells as an energy source.



Body's energy consumption at rest. Brains need a great deal of energy at all times.

In addition to energy, we need building materials, especially for the development and maintenance of our skeletal and muscular systems. Proteins are the most important group of such building materials. They are broken down into amino acids, which the human body uses to grow and to repair itself. Protein digestion occurs in the stomach and the small intestine.

Fats are the third major nutrient group. Digestion of fats takes place in the small intestine. The digestion of fats is helped by bile produced in the liver. Bile breaks the fat into small droplets that are easier for enzymes to work on.




Parts of the digistive system.