How does insoluble fiber impact gastric emptying?

• A. Consumption of insoluble fiber results in decreased gastric emptying
• B. Insoluble fiber delays only small intestine transit
• C. Insoluble fiber has no effect on gastric emptying
• D. Insoluble fiber increases gastric emptying

Answer: (A)

Insoluble fiber adds bulk in the stomach. Its particulate, non-dissolving nature means the stomach has to work harder to churn and grind this material before it can move chyme into the small intestine. That extra bulk slows the rate at which the stomach can empty, so gastric emptying is decreased. It isn’t primarily about delaying transit in the small intestine, it isn’t no effect, and it isn’t about increasing emptying—the bulk from insoluble fiber tends to slow the process.