Mechanisms and disorders of gastric emptying.

The stomach converts food into fragments and then liquifies it before emptying it into the duodenum. Gastric emptying of liquid foodstuffs is so controlled that about 200 kcal/hr are delivered to the duodenum. The volume of the meal, its energy density (kcal/ml), and the proportions of fat, carbohydrate, and protein in the meal have minor effects on the rate of gastric emptying of energy. Regulation is achieved through the osmotic effect and calcium binding of the products of digestion in the duodenum. There are no receptors that respond to energy.