Increasing wholegrain foods in the diet primarily helps by what mechanism?

• A. Increases acid production
• B. Stimulates peristalsis
• C. Reduces enzyme activity
• D. Slows digestion

Answer: (B)

Increasing wholegrain foods raises dietary fiber, which adds bulk to the stool and holds water. This bulk stretches the walls of the gut, triggering the gut’s smooth muscle to contract in a wave-like pattern called peristalsis. Those contractions move waste along more quickly, leading to more regular and easier bowel movements. That is the main way higher grain intake supports digestion. The other potential effects—like changes in acid production or enzyme activity, or slowing digestion in some contexts—are not the primary mechanism by which this dietary change improves bowel function.