Biochemical processes in the body by which fats ingested in the diet are broken down (first into fatty acids and glycerol and then into simpler compounds) into substances that can be used by the cells of the body. Fats are a major energy source, providing approximately 9 kilocalories per gram, compared with about 4 kilocalories per gram for carbohydrates.
The sum of the physical and metacarpal chemical changes involved in the breakdown and synthesis of fats in the body. Dietary fats are digested to fatty acids and glycerol in the small intestine, absorbed, and reformed into triglycerides that are transported in the form of chylomicrons. Fats may be stored in adipose tissue as potential energy or may be broken down to provide immediate energy. The liver has enzymes for the beta-oxidation of fatty acids and their use in the Krebs cycle. Fats may be formed from excess dietary carbohydrate or amino acids. Synthetic reactions produce phospholipids and steroids.