A simple at-home corn test to measure how long food takes to travel through your digestive tract.
The time it takes for food to move from your mouth all the way through your digestive system.
Bowel transit time is one of the simplest, most useful markers of digestive health. A slow transit time means stool spends longer in the gut, which can contribute to bloating, discomfort, and constipation. A balanced transit time supports regular elimination and a healthier microbiome.
The corn test is an easy, food-based way to measure your transit time at home without having to spend money on lab testing
Four simple steps using corn as a visual marker.
At dinner, eat ½ cup of corn kernels (canned or frozen/reheated). You can mix the corn into a meal or eat it on the side. If eating it on the side, chew only enough to swallow.
Write down the date and time you ate the corn. You can use your phone, a notes app, or a bowel movement tracking app.
Watch for corn kernels in your stool over the next few days. The kernels may appear lighter in color, and you may only see a small amount. This is completely normal.
Your transit time is the amount of time between eating the corn and seeing the last of the corn pass in your stool.
If you eat corn on Monday at 6:00 PM and stop seeing corn in your stool on Wednesday at 8:00 AM, your transit time is 38 hours.
Compare your transit time to these general ranges.
Putting your transit time into context.
In general, the longer your transit time, the more backed-up stool may be present in the digestive tract.
If your transit time is prolonged, a bowel "clear out" may be recommended before starting a daily motility supplement.
We recommend repeating this test every 2–4 weeks to track your progress over time.
Consider a clear out if:
Do NOT Perform A Clear Out If You Have:
Seek medical attention if these are present.
Transit Time 36-60 Hours
Option A (Preferred First Choice)
Magnesium Citrate Rescue
For otherwise healthy adults:
Transit Time >60 Hours
Option B (Preferred)
PEG (Miralax/Restoralax/Macrogol) Rescue
Mix:
Drink:
Most people respond within 2-12 hours, though some may not respond until the following day.
Severe Stool Retention / Prior Failure
If you have:
You may consider:
PEG protocol + 2 Dulcolax (bisacodyl) tablets
Do
Avoid
Resume your usual bowel support the following day:
Examples:
Repeat your transit time test 2–7 days after the clear out.
Success =
If:
Consider:
Investigating other possible root causes:
If multiple rescue attempts fail, further medical evaluation is warranted.
It may take a couple days for things to settle down, but we should be seeing less gas, bloating, etc…
Resume your normal motility agent that night:
For the next 7 days, it’s CRUCIAL to be locked in with your diet, hydration, and morning routine to take advantage of the clear out and normalize your bowels.
Eat a fiber-rich breakfast like a smoothie using the following ingredients:
Start with the lowest amount of all of these foods to ensure your gut has time to adjust and get used to the increased fiber.
The rest of the day, you should be eating good sources of fiber, healthy fats, & potassium. Aim to have 2-3+ foods from these lists daily.
Fiber Foods
Healthy Fats for Constipation
Potassium-Rich Foods
A simple rule of thumb after a clear out is to aim to include at least 2–3 potassium-rich foods daily, as adequate potassium intake can help support healthy muscle contractions and bowel motility.
