10 Foods that are Harmful to Your Digestive System

Not all foods are created equal. Even though we consume food for nourishment and pleasure, it is important to be aware that certain foods are less than ideal for our digestive system and overall health. With regards to food, the saying ‘you are what you eat’ could not be truer.

Here is a list of 10 foods that can negatively affect your digestive health.

  1. Processed meat

processed meat

If taken in moderation, red meat that has been prepared in a healthy manner can be good for your body. It is rich in protein, iron, minerals and certain B vitamins that are not found in plant based foods. However, red meat consumption has been associated with an increased risk of colorectal cancer. Up to now, there are still lots of questions and criticisms about the carnivore diet. Processed meats – red meat products that have been cured, smoked or salted to improve longevity and taste, are especially bad. All that processing changes the nutritional profile of the meat, making it into an unhealthy food product. Studies have also linked processed meat with a higher risk of developing chronic diseases such as diabetes mellitus, heart disease and certain types of cancer (1).

  1. Canned foods

Popping open a can of food and reheating it may be a convenient way to get dinner on the table, but it is certainly not the healthiest. People who regularly consume canned foods have been found to have higher levels of Bisphenol A (BPA) in their body. BPA is an industrial chemical that has suspected links with several metabolic diseases such as heart disease, obesity and diabetes (2). It is also directly harmful on your digestive system. A study done on BPA exposed pregnant rabbits found that the rabbit offspring had significantly reduced levels of good bacteria in the gut, which may lead to increased gut permeability and inflammation (3).

  1. Certain medications

Although medications have therapeutic effects that can make us feel better when unwell, most of them also have unpleasant side effects. NSAIDs such as ibuprofen, naproxen, aspirin and oral steroids are all common culprits that can trigger episodes of heartburn. Antibiotics, if used unnecessarily or inappropriately, are also harmful as they are known to negatively affect the collection of microbes living in your gut causing imbalances in your gut microbiome (4) Unless antibiotics are absolutely necessary, here are some safer alternatives. (https://www.seleneriverpress.com/freedom-from-antibiotics-an-easy-guide-to-safer-alternatives/ )

  1. Food additives

Instant food and processed foods are unfortunately common in today’s modern diet. To make foods that taste good even after long periods of time while still maintaining a profitable cost margin, food manufacturers rely heavily on food additives. Several studies (5, 6) have investigated the effects of these additives, which include metal oxide nanoparticles, sodium chloride, surfactants, polysorbate 60 and polysorbate 80, on the intestinal mucosa of the gut. These studies found that food additives have harmful effects on intestinal permeability and can cause impaired gut barrier function. To put it in layman’s terms, food additives are simply not good for your gut.

  1. Foods with high sugar content


Regular table sugar is usually made up of sucrose, a disaccharide of glucose and fructose. Even though sweetened food and drinks may taste better, avoiding sugar is a healthier choice for better digestive health. A study done on rats found that sugar significantly altered the community of microbes living in the gut (7). Even worse, it goes beyond your gut as high fructose corn syrup has been linked to generally increased levels of inflammation (8).

  1. Food colouring

Appearances can be deceiving. Brightly coloured foods, while pleasing to the eye, may contain chemical food colouring that can have bad effects on your health. Research has linked food colours with hyperactivity and ADHD in children as well as cancer causing contaminants in animal studies (9). The fact that certain dyes are allowed in one country but banned in another country makes the safety of food colours even more dubious. For example, dyes red 40, yellow 6 and yellow 5 are banned in the European Union but commonly used in the US.

  1. Artificial sweeteners

Sugar substitutes are substances that sweeten food and drinks like regular table sugar, but without the high number of calories. These can be naturally sources, like stevia, or chemically synthesized sweeteners such as aspartame, Acesulfame potassium (Ace-K) and sorbitol. Animal studies have found that artificial sweeteners can cause unhealthy changes in the gut microbiome (10). These changes have been linked with poor glucose tolerance, putting you at higher risk of developing diabetes.

  1. Greasy or fatty foods

This includes foods like fried foods, rich or oily sauces and very creamy desserts. Although these delicacies may taste delicious, they are unhealthy for your gut and your body as in general. Frequently eating calorie rich foods can cause weight gain and obesity, which is associated with a whole host of unwanted conditions such as diabetes, heart disease and stroke. If you are prone to developing gallstones, foods rich in fat will only make things worse. Fatty foods are also heavy on your gut and difficult to digest. Too much of grease can even cause unpleasant digestive symptoms such as diarrhoea.

  1. Excessive alcohol consumption


Any food if consumed in excess will have negative consequences on the body. This is especially true in the case of alcohol. The recommended amount of alcohol by the USDA Dietary Guidelines is 1 drink a day for women and up to 2 drinks a day for men. Excess alcohol consumption can cause nausea, heartburn and possibly lead to alcohol dependence or abuse.

In 1998, a small study was done to investigate the connection between alcohol abuse and IBS. They found IBS to be present in almost half the patients (42%) with alcohol dependence, whereas only 1% of patients without alcohol dependence complained of IBS symptoms (11).

  1. Dairy

Dairy products including milk, cream and soft cheeses can cause digestive trouble as they contain a milk sugar called lactose. As it is rich in vitamin A, D, calcium, phosphorus and many other nourishing compounds, dairy can be a good source of nutrients, but it can also cause digestive problems in people who are lactose intolerant. If your gut has insufficient lactase to break down the lactose you consume, you may experience symptoms like bloating, abdominal discomfort or even diarrhoea when you consume dairy.


These are just a few foods that may cause trouble for your digestive tract. Depending on your individual health needs, the best and worst foods for your digestive health may differ. However, it is undeniable that a happier gut often translates to better overall well being and increased quality of life. Therefore, before eating a snack or having your meal, take a moment to truly consider whether the food you are going to eat is healthy for your body.


  1. https://www.ncbi.nlm.nih.gov/pubmed/26621069
  2. https://www.ncbi.nlm.nih.gov/pubmed/26026606
  3. https://chemicalwatch.com/crmhub/60019/bpa-may-change-gut-microbiota-and-metabolites-study-suggests
  4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4709861/
  5. https://www.ncbi.nlm.nih.gov/pubmed/30504122
  6. https://www.ncbi.nlm.nih.gov/pubmed/6094320
  7. https://www.ncbi.nlm.nih.gov/pubmed/27903830
  8. https://www.ncbi.nlm.nih.gov/pubmed/25515398
  9. https://www.healthline.com/nutrition/food-dyes
  10. https://www.ncbi.nlm.nih.gov/pubmed/27090230
  11. https://www.ncbi.nlm.nih.gov/pubmed/9741950

Author Bio

Dr. Praveena Asokan is a writer with a background in clinical medicine. After graduating with a medical degree (MBChB) from the University of Leicester (UK) in 2014, she worked in various hospitals in Wales and Malaysia as before transitioning into medical research. This helped her shift into a writing career, and she now enjoys researching and writing on a number of health-related topics.

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