Final answer:
Liquids are restricted during meals after a gastrectomy to avoid speeding up the stomach's emptying rate, which could overwhelm the small intestine's processing capability.
Step-by-step explanation:
Liquids are restricted during meals following a gastrectomy because they can speed up the emptying rate of the stomach. During the gastric emptying process, the pylorus regulates the release of chyme into the duodenum by allowing only small amounts at a time, which is essential for efficient chemical digestion and to prevent overloading the small intestine. When liquids are consumed with meals, they can pass through the pylorus more quickly than solid food, potentially leading to a rapid delivery of chyme that overwhelms the small intestine's capability to effectively process it.