What is the process of breaking down food called?

The process of breaking down food is called digestion. It changes food into smaller molecules that the body can absorb and use for energy, growth, and cellular repair.

Digestion begins in the mouth, where teeth mechanically break food apart and saliva starts chemical digestion. After swallowing, food passes through the esophagus to the stomach, where acids and enzymes continue breaking it down. The small intestine is the main site of chemical digestion and nutrient absorption; tiny projections called villi increase its surface area.

Digestion has both mechanical and chemical parts. Chewing and muscular contractions physically mix and move food, while enzymes split carbohydrates, proteins, and fats into smaller components. The pancreas and liver assist by supplying digestive enzymes and bile.

Digestion is sometimes confused with absorption. Digestion breaks food into usable molecules, whereas absorption moves those molecules—such as glucose, amino acids, fatty acids, vitamins, and minerals—into the blood or lymph.