Using the conversion assumption provided in a research brief that each additional 10 g/day of dietary fiber increases average daily stool wet weight by approximately 20 g/day, estimate the expected increase in stool wet weight if a person increases fiber intake from 12 g/day to 30 g/day. Show calculations.

• A. Approximately 20 g/day increase in stool wet weight since any fiber increase beyond 10 g plateau quickly.
• B. Approximately 72 g/day increase in stool wet weight because each gram of fiber increases stool mass by 4 g under physiological conditions.
• C. Approximately 36 g/day increase in average stool wet weight.
• D. No change in stool wet weight because fiber only affects stool frequency but has no measurable effect on mass.

Answer: (C)