Gut transit time DIY test
Gut transit time test: a simple DIY test to see how long food stays in your body
Most people judge their digestion by one thing…
“Do I go to the toilet every day?”
But daily bowel movements don’t necessarily mean digestion is working efficiently. In fact, many people who go to the bathroom every day still have food from several days earlier sitting in their digestive tract. The time it takes for food to travel from mouth to stool is one of the simplest indicators of digestive health.
What is gut transit time?
Gut transit time refers to how long food takes to move through your digestive system. Digestion occurs in several stages:
• stomach
• small intestine
• colon
Research measuring digestive motility suggests approximate transit times of:
Stomach emptying: 2–5 hours
Small intestine: around 4 hours
Colon: roughly 20–40 hours
Overall, whole-gut transit time in adults typically ranges between 10 and 73 hours, with an average around 28 hours. However, most of these studies measure people eating typical Western diets, so these numbers reflect population averages rather than optimal digestive function.
Many practitioners believe that a transit time of 12–24 hours to reflect efficient gut motility.
Why gut transit time matters
When food moves too slowly through the digestive tract, it remains in the colon longer. This allows bacteria more time to ferment undigested food. This fermentation can contribute to symptoms such as:
• bloating
• gas
• sluggish digestion
• irregular bowel movements
Slow gut motility may also be associated with factors such as chronic stress, dehydration, low stomach acid, sluggish bile flow, or diets high in ultra-processed foods.
A simple DIY gut transit time test
One of the easiest ways to estimate digestive transit time is the sesame seed test. Sesame seeds pass through the digestive system largely intact, making them easy to identify later.
How to do the sesame seed transit test
On a normal eating day, swallow one tablespoon of whole sesame seeds without chewing them. White seeds are easier to see but black can work just as well.
Record the time you eat them.
Check your bowel movements afterwards.
Note when the seeds first appear in your stool.
The time between eating the seeds and seeing them again gives you an estimate of your gut transit time.
A more accurate at-home digestion test
For a clearer picture, you can use three food markers over three days, best eaten at the same time each day.
Day 1: sesame seeds
Day 2: beetroot
Day 3: sweetcorn
Each food acts as a visible marker. Ideally, they should appear in your stool in the same order you ate them, indicating coordinated gut motility.
Supporting healthy gut motility
Your digestive system has a natural mechanism called the gastrocolic reflex. When food enters the stomach, signals are sent to the colon encouraging it to empty. This reflex is strongest in the morning, which is why many people feel the urge to go to the toilet after breakfast. Eating a protein- and fat-containing breakfast within an hour of waking can help stimulate this reflex and support regular bowel movements.
What if your transit time is slow?
If food is taking longer than 36–48 hours to pass through the digestive system, it may be a sign that digestion needs additional support. Improving gut motility usually involves addressing the overall digestive environment, including diet quality, microbial balance, and digestive function. One of the most effective starting points is simplifying the diet and focusing on whole, nutrient-dense foods that support digestion.
Supporting your gut with the 30-Day Gut & Metabolic Reset
If you want a structured way to support digestion, my 30-Day Gut & Metabolic Reset focuses on removing common dietary irritants and replacing them with deeply nourishing foods that support gut and metabolic health. The reset eBook includes over 40 recipes designed to be gentle on digestion while providing nutrients that support the gut microbiome, bile flow, and overall digestive function.
Many people find that when they simplify their diet and prioritise gut-supportive foods, symptoms such as bloating, sluggish digestion, and irregular bowel movements begin to improve.