This document discusses the digestion of different types of food. It notes that food is broken down into simpler molecules so they can be absorbed by the small intestine. Carbohydrates are broken down into glucose, proteins into amino acids, and fats into glycerol and fatty acids. Different parts of the digestive tract secrete enzymes that break down specific foods - amylase breaks down starch in the mouth and small intestine, protease breaks down proteins in the stomach and small intestine, and lipase breaks down fats in the small intestine.