The majority of fat digestion occurs in which part of the digestive tract?

• A. Ileum
• B. Mouth
• C. Colon
• D. Duodenum

Answer: (D)

Fat digestion relies on emulsification and enzymatic breakdown, and the duodenum is where these processes happen most extensively. When chyme enters the duodenum, bile salts emulsify fats, greatly increasing their surface area, and pancreatic lipase hydrolyzes triglycerides into monoglycerides and free fatty acids. The contributions from the mouth (lingual lipase) and stomach (gastric lipase) are relatively small, so they don’t match the bulk of fat digestion that occurs in the duodenum. Absorption mainly occurs further along the small intestine, but the major digestion step takes place in the duodenum due to the presence of pancreatic enzymes and bile.