Where does the major digestion of fat begin?

The major digestion of fat begins in the small intestine due to the action of bile acids and pancreatic lipase. When fat enters the small intestine, bile produced by the liver is secreted into the small intestine and helps emulsify large fat globules, breaking them into smaller droplets. This process increases the surface area for lipase enzymes to work effectively.

Pancreatic lipase, which is secreted by the pancreas into the small intestine, then breaks down triglycerides into monoglycerides and free fatty acids, which can be easily absorbed by the intestinal cells. This is the main site where fat digestion occurs, with the small intestine playing a crucial role in the absorption and processing of dietary fats.

In contrast, minor fat digestion begins in the mouth with lingual lipase, but this process is not substantial enough to be considered major. The stomach does contribute to some mechanical mixing and a little bit of enzymatic action, but it is not where most fat digestion takes place. The large intestine has no significant role in fat digestion, as any remaining undigested fats are typically excreted. Thus, the small intestine is accurately identified as the primary site for fat digestion.