What Happens to Food That Passes Through the Digestive System Without Being Digested and Absorbed?

Your digestive tract works around the clock to break apart the foods you eat and absorb nutrients. But sometimes, those foods travel through without ever being digested. It’s unusual to pass along undigested food. If you go for too long without getting a diagnosis and treatment, you could become malnourished.

Where It Goes

Food that passes through your digestive tract without being broken down usually looks the same way going out that it did going in. This means that you’ll see food particles in the toilet when you have a bowel movement. You might have solid stools that are full of these pieces. On the other hand, you could have loose, watery stools filled with random food particles, as well.

The Causes

All kinds of things can cause poor digestion and malabsorption, from physical to biological factors. It might be a problem with the way you eat. If you’re scarfing down your food and not chewing thoroughly, you’re just making things harder on your digestive tract. Sure, your stomach and intestines can still digest the food somewhat, but whatever particles they can’t break down come straight out in your stools. Poor digestion and absorption can also stem from a food allergy or intolerance, since these conditions can lead to severe irritation in your gut as your body tries to pass the allergenic foods. Chronic bowel issues, such as Crohn’s disease or irritable bowel syndrome, can also inhibit digestion and nutrient absorption.

Fiber Consideration

Fiber is a component in food that never gets broken down and absorbed. So if you eat something high in fiber, you might see those indigestible particles floating in the toilet, especially if you don’t regularly consume fiber and your body doesn't know how to process it. This is more likely to happen when you have foods that are high in insoluble fiber, which is known to speed up digestion and stay intact in your gut -- think corn, lettuce, nuts and seeds. These insoluble-fiber-rich foods might leave pieces behind in your stools, simply because the human body isn’t able to digest them. Plus, if you don’t chew thoroughly, the fibrous parts are likely to sweep right through your bowels, pushing out other foods that haven’t been digested yet.

What Can Go Wrong

If large particles in your stool or loose stools seem like an everyday occurrence for you, you’ll need to let your doctor know. If your body isn’t digesting food properly, no matter how balanced your diet is, you won’t be getting the nutrients you need. You might start feeling groggy as your glucose levels drop, if you’re not properly digesting carbohydrates. Problems with growth, wound healing and development can also occur without absorption of protein, vitamins and minerals. Your body may burn off stored fat initially, leading to weight loss. But once that fuel is gone, your system might start using up muscles for energy, in severe cases.


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