I have a food intolerance and get diarrhoea from certain foods. Am I absorbing calories or nutrition from those foods?

If foods move too quickly through your small intestine without having time to be digested and absorbed, you may not be getting all the calories and nutrients you should.

Most of your nutrients and calories are absorbed in your small intestine, so in an ideal scenario, food travels through here at a steady rate.

If it's moving too quickly without having time to be digested and absorbed, you may not be getting all the calories and nutrients you should.

Identifying the cause of your symptoms

Think of the gut like a long pipe that runs north to south, starting in the mouth, where we produce digestive enzymes in our saliva.

At what point in the journey of your food are the reactions happening?

If it's after 10 hours, that’s probably in your large intestine. Here, there can be issues with absorbing water and imbalances in your gut bacteria, leading to excessive fermentation which produces symptoms like bloating and diarrhoea.

So while absorption of nutrients happens in the small intestine, the large intestine focuses on fermentation, producing compounds like short-chain fatty acids which are vital to gut health.

However if your microbes down there are imbalanced—what we call dysbiosis—that fermentation that can often draw more water into the colon, causing diarrhoea.

Even if your gut symptoms are severe, it’s likely that you’re absorbing a fair amount, if not all of the nutrients in what you’re eating. But that doesn’t mean that you should ignore gut symptoms like diarrhoea, constipation or bloating. They’re a sign that your gut needs attention.

Absorbing nutrients is far from the only job of your gut: the bacteria in your large intestine control many elements of the health of your whole body, and your mind too.

Get a window into your gut health

If you'd like to find out the types and levels of bacteria and other microbes in your large intestine, and see what's going on with your digestion, inflammation and much more, check out our Gut Health Tests.