How Long Poop Stays In Your Body May Matter For Your Health

A “normal” poop schedule varies a lot from person to person. The NHS says anything from three times a week to thrice a day can be normal, especially if they’re smooth, easy-to-pass bowel movements.

But according to a 2023 review published in the journal Gut, people’s “gut transit time” might be key to learning about their gut health.

They think that differences in how long it takes people to pass a bowel movement might explain “large proportions of the gut microbiota compositional variation between people,” which may itself be linked to health issues.

What might my poop schedule say about my health? 

The researchers looked at previous research that tracked how long it took food to pass through participants’ systems, as well as their microbiomes and conditions like IBS and cirrhosis of the liver. 

They found that people whose food’s journey from mouth to loo took a little longer tended to have more bacteria that feed on protein. And those with lower-fat, higher-carb diets seemed to have a faster transit time. 

Both very fast and very slow transit times were linked to less diverse microbiomes.

Constipation and diarrhoea, as well as changes to the microbiome, are linked to multiple health conditions, like Parkinson’s, the researchers added. 

That’s a bit of a “chicken and egg” issue: we don’t know whether the disease causes the gut change, or the other way around, or a bit of both. 

But, they argue, research like this can help them get a “better understanding of the complex, bidirectional interactions between the gut microbiota and transit time is required to better understand gut microbiome variations in health and disease”. 

Other research found a pooping “sweet spot” 

A separate 2025 study linked longer stool transit times to the release of “toxins” into the bloodstream. 

“If stool sticks around too long in the gut, microbes use up all of the available dietary fibre, which they ferment into beneficial short-chain fatty acids. After that, the ecosystem switches to fermentation of proteins, which produces several toxins that can make their way into the bloodstream,” possibly harming our organs. 

And those with diarrhoea were more likely to have higher levels of chemicals linked to liver damage. 

Pooping once or twice a day, meanwhile, was linked to better gut health and overall health.