Through the gastrointestinal system, the nutritional substances, minerals, vitamins, and fluids, enter the body. Lipids, proteins, and complex carbohydrates are broken down into small and absorbable units (digested), principally in the small intestine.

Where does most macronutrient digestion occur?

The small intestine is the primary site of carbohydrate digestion. Pancreatic alpha-amylase is the primary carbohydrate digesting enzyme.

How are macros digested?

When food is digested, the protein is broken down into amino acids; the fat is broken down into fatty acids; and the carbohydrate is broken down into glucose. It is easy to see, then, that most of the glucose (sugar) in your blood comes from the carbohydrate in foods.