What effect does dietary fiber have on gastric emptying?

• A. Dietary fiber accelerates gastric emptying
• B. Dietary fiber results in delayed gastric emptying
• C. Dietary fiber reduces gastric emptying
• D. Dietary fiber has no effect on gastric emptying

Answer: (B)

Dietary fiber slows how quickly the stomach empties, especially the soluble, viscous types (like psyllium, oat β-glucans, and pectins). These fibers form a gel in the stomach, increasing chyme viscosity and keeping contents more cohesive. This makes the pyloric pump work more slowly and the rate of transfer into the small intestine decreases, delaying gastric emptying. The result is a longer gastric residence time and a slower rise of chyme in the duodenum, which can also help with satiety and glycemic control. Insoluble fiber tends to have less impact on gastric emptying, since it mostly affects stool bulk and transit further down the GI tract. So the best description is that dietary fiber delays gastric emptying.