The human digestive system breaks down food through physical and chemical digestion. Physical digestion involves chewing and stomach churning while chemical digestion uses enzymes to break foods into smaller molecules. Digestion begins in the mouth and travels through the esophagus, stomach, and small and large intestines. In each section, glands secrete enzymes to break down carbohydrates, proteins, and fats into smaller molecules like glucose, amino acids, and fatty acids that the body can absorb.