Gut transit time is how long food takes to travel from mouth to toilet, and it varies far more between people than most would guess. The average sits around 23 to 24 hours, but a healthy range spans anywhere from 12 to 73 hours.[1]
One low-tech, at-home way to measure your own is the sweetcorn test. Corn kernels have an outer shell that resists digestion, so they pass through mostly intact and stay visible in stool, giving a rough but real timestamp.
Avoid corn for 7 to 10 days first, so any residue from past meals doesn't confuse the result.
Eat a measured portion of corn, on the cob or a handful of kernels, and note the exact time.
Check each bowel movement afterward for visible kernels, and note the time you first see them.
A result at 12 hours or faster suggests accelerated motility, sometimes linked to anxiety, IBS, or in some cases inflammatory bowel disease. Mention it to a doctor if the pattern repeats, rather than showing up just once. A result past 48 hours suggests sluggish motility, which can allow more time for gas-producing fermentation and bloating, and often responds to more fiber, more water, and more movement over the following weeks.
One test isn't a diagnosis either way. Diet, stress, illness, and travel all shift transit time temporarily, so a single unusual result is information, not an alarm.
What to do with this
Run the sweetcorn test once and note where you land on the 12-to-73-hour range. If you're under 12 hours or over 48 hours across two attempts a few weeks apart, bring that specific number to a doctor rather than a vague complaint about digestion. If you land in the 18-to-36-hour range, which covers most people, no action is needed beyond the usual: steady fiber, regular water, and daily movement.
- "How Well Is Your Gut Working? There's a Grossly Simple Way to Check." ScienceAlert. sciencealert.com
