The 5 Worst Foods for Your Gut and What to Eat Instead

Your gut microbiome is the community of billions of microorganisms (such as fungi, bacteria, and viruses) that live in your gut. These microbes play a key role in digestion, immunity and overall health. What you eat greatly affects this balance. Foods like red meat, ultra-processed foods, alcohol, artificial sweeteners, and dairy can harm your gut health..

Eat red meats like beef, lamb and pork can increase certain toxins in your gut. Gut microbes convert L-carnitine, an amino acid found in red meat, into a harmful compound called trimethylamine-N-oxide (TMAO). TMAO can lead to hardening of the arteries and an increased risk of heart disease.

Eat processed red meat (bacon, sausage, pepperoni) may also increase levels of certain gut microbes that contribute to inflammation and increase the risk of colorectal cancer.

Ultra-processed foods are industrially manufactured, ready to eat or reheat. They contain little or no whole foods and are often high in saturated fat, added sugars, sodium (salt), and other additives this can harm the gut microbiome. Eating a lot of it can increase your risk of heart disease and obesity. Examples include:

• Soft drinks
• Fast food
• Chicken nuggets
• Hot dogs
• Candy

Ultra-processed foods can reduce the quantity and diversity of “good” intestinal microbes. This can lead to intestinal inflammation and increased intestinal permeability, meaning more harmful substances are absorbed into the bloodstream. This can increase the risk of diseases like obesity, dementia and Alzheimer’s disease.

Studies show that long-term alcohol consumption significantly modifies the gut microbiome.

Alcohol decreases helpful gut microbes and increases harmful microbes. It can also lead to increased intestinal permeability, which can allow harmful substances to enter the bloodstream.

Sugar-free, zero-calorie sugar substitutes may cause an imbalance in the gut microbiome, increase inflammation, and reduce helpful short-chain fatty acids (SCFAs), which support digestive health.

Risk of diabetes: The use of artificial sweeteners has been linked to an increased risk of obesity and type 2 diabetes, and these effects may start in the gut. In experiments, when gut microbes from hosts who had consumed low-calorie sweeteners were transferred to healthy mice, the glucose (sugar) tolerance of these mice weakened.

People with certain pathologies may have difficulty digesting dairy products:

• Lactose intolerance: Lactose is a sugar found in dairy products. About 70% of adults worldwide do not have enough intestinal lactase, the enzyme needed to digest lactose. For these people, foods high in lactose like milk and cheese can trigger gastrointestinal (GI) symptoms such as bloating, diarrhea, and abdominal pain.
• Allergy to milk and dairy products: Milk is one of the most common allergies. People with milk allergies may experience gastrointestinal symptoms from dairy products, such as abdominal pain, vomiting, and diarrhea.
• Inflammatory Bowel Diseases (IBD): People with Crohn’s disease or ulcerative colitis (UC) may have difficulty digesting lactose. These conditions cause inflammation of the gastrointestinal tract. Avoiding trigger foods like dairy can help prevent flare-ups and manage IBD symptoms like nausea, abdominal pain and diarrhea.

Certain foods promote gut health, such as:

• Probiotic foodsincluding yogurt and fermented foods like kefir, kimchi, kombucha, tempeh and sauerkraut. Probiotics are live microorganisms that change the composition of your gut microbiota, reducing the growth of harmful bacteria and allowing helpful bacteria to thrive.
• Prebiotic foods, such as bananas, onions, barley, garlic, leeks and asparagus. Prebiotics helps feed the “good” probiotic bacteria in your gut and change your intestinal pH, preventing the growth of harmful microbes. These changes lead to a reduction in gut inflammation and may increase the production of intestinal glucagon-like peptide 2 (GLP2), a hormone that helps strengthen the intestinal lining.
• Foods rich in fiberincluding whole grains, fruits, nuts, seeds, leafy greens and other vegetables. Dietary fiber is a non-digestible carbohydrate that improves satiety (fullness) and supports gut health.
• Foods rich in polyphenolslike apples, berries, cocoa, artichokes, tea, citrus fruits and pears. Polyphenols are antioxidants produced by certain plants. These natural compounds help balance “good” and “bad” microbes in the gut, strengthening the immune system and helping prevent diseases like colorectal cancer.