13 Foods That Are Terrible For Your Gut Health

Unhealthy Food | Probiotic Supplements

6 min read

A healthy gut is the cornerstone of a healthy body: when your gut microbiome is balanced and diverse, almost every other system in your body benefits. Similarly, an unbalanced gut can wreak havoc on everything from your metabolism to your mood. What you eat plays a huge role in the health of your gut. Supporting your gut with good bacteria such as a probiotic supplement is essential.

One of the best ways to support your gut health is to eat well. Here are 13 foods with the highest potential to damage or disrupt your gut microbiome - and therefore avoid. 


Refined white sugar may have a particularly bad reputation, but it turns out that sugar in any of its forms is potentially harmful to your gut health. Participants in a study of sugar's effects on digestion reported increased constipation and poorer overall gut function while on a high-sugar diet.

Processed Foods

Most of us know that processed foods aren't exactly healthy, but the effects that they can have on your digestive system balance might surprise you. A recent study conducted on mice revealed that the emulsifiers used in heavily-processed foods disturbed their gut microbiota so much that many developed colitis and metabolic diseases.


While sugar and processed foods are generally regarded as unhealthy, soy is often thought of as nutritious and beneficial. However, the high levels of processing that much of today's soy goes through has changed how it affects the body. In fact, high levels of soy in your diet can have deleterious effects on your gut microbiome as the ingredient has been shown to reduce key Bifidobacteria and Lactobacillus populations, two strains that are crucial for a balanced gut.


Even if you aren't lactose intolerant, dairy may not be the best choice for your stomach. Studies have shown that dairy consumption changes the bacterial makeup of your gut within days, allowing strains linked to intestinal disease and inflammation flourish.

Red Meat

Like dairy, eating red meat can encourage the growth of certain bacterial strains that can negatively impact your health, from your weight to your immunity to your emotional state. The same study that found dairy to be problematic showed that red meat had the same ill effects on study participants’ gut microbiomes.


Gluten--a protein found in a number of grains such as wheat and barley--has gotten a bad rap in recent years, and it turns out this reputation is unfortunately well-earned. While those with Celiac disease are particularly susceptible to its effects, studies have found that gluten can lead to stomach pain, bloating and fatigue even in those without the disease.


While concerns about eggs raising bad cholesterol levels may have been debunked, new research indicates that eating eggs may lead to heart disease in a different way. Cleveland Clinic researchers found that a certain protein in eggs encourages the growth of gut bacteria that produce a chemical compound that causes clotting and thus raises the risk of heart attack and stroke.6

Genetically-Modified Organisms (GMOs)

In an effort to cultivate crops that are naturally resistant to pests and disease, scientists have created what are known as genetically-modified organisms (or GMOs); wheat, soybeans and corn are the three most common GMOs in the United States. Unfortunately, the traits that help GMOs resist disease can have terrible effects on gut health: studies have found that consumption of GMO foods can reduce the beneficial bacteria populations in the gut.


The reason that corn can be so detrimental to your gut health is simple: almost 90% of all corn grown in the United States is genetically modified. The prevalence of corn in the American diet--and the general fuzziness surrounding what is and isn't genetically modified--suggests that avoiding corn altogether might be the best choice for your gut health.

Farmed Fish

While the taste and availability of farmed fish and wild fish differ greatly, one major distinction between the two explains why farmed fish can be bad for your gut: the use of antibiotics in aquaculture. Huge amounts of antibiotics are included in the food that farmed fish are fed, and evidence suggests that these antibiotics can be passed along when these fish are eaten. Of course, any antibiotic kills the bacteria in your gut indiscriminately, leading to an unhealthy balance of key strains.


Plants in the nightshade family such as tomatoes, eggplant, potatoes and bell peppers are generally thought to be an important part of a healthy diet, but one key ingredient in all of these foods has the potential to cause serious gut issues. Naturally-occurring glycoalkaloids found in all nightshades have been shown to lead to intestinal inflammation and the condition known as "leaky gut" in mice, raising concerns about their effects on the human digestive tract.

Tap Water

Staying hydrated by drinking enough water is obviously necessary, but you should be careful about the source of the water you drink. The water that comes from your tap is treated with a host of chemicals including chlorine, and research has found that chlorinated water can alter gut microbiota and even lead to the development of colorectal cancer.

Artificial Sweeteners

Many people trying to lose weight turn to artificial sweeteners; after all, what could be bad about these zero-calorie treats? Quite a lot, as it turns out. Research increasingly points to a host of negative gut effects caused by artificial sweeteners, including changes to gut microbial composition, increased glucose intolerance and higher rates of metabolic disease.

Of course, avoiding all of these ingredients all the time is practically impossible, particularly if you enjoy a good pizza or bowl of ice cream every now and then. However, taking steps to reduce your intake of these foods and adding in a daily probiotic supplement to help preserve your beneficial gut bacteria can go a long way towards a healthier gut.


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