Worst Foods for Gut Health

You are what you eat.

It’s long been said that you are what you eat, and nutritional science is increasingly finding that there’s a lot of truth to that axiom. The gut — more specifically, the diverse microbiome of bacteria that reside within it — can have far-reaching health impacts, including on heart and brain health.

Aderet Dana Hoch, a New York-based registered dietitian and founder of Dining with Nature by Aderet, says “strong gut health is linked to many benefits, such as improved immune, heart, brain and reproductive health. A healthy gut is also linked to enhanced mood and better sleep.”

Your gut is home to many organisms.

Everyone has a microbiome, which is a collection of more than 100 trillion microbes that live on and in your body. The majority of these microbes live in the large intestine. This means your gut is full of trillions of tiny organisms — you have between 300 and 500 different strains of bacteria in your colon — which help your gut carry out its work.

Certain foods, such as sauerkraut, yogurt and fresh fruits and vegetables, help foster a healthy gut microbiome, while other food and beverages may have a negative effect.

Eating for good gut health

Supporting a healthy gut microbiome has been associated with reduced risk for certain diseases, such as Alzheimer’ and other forms of dementia, cancer and metabolic diseases like obesity.

Dana Ellis Hunnes, a senior clinical dietitian at UCLA Medical Center, assistant professor at UCLA Fielding School of Public Health and author of “Recipe For Survival,” notes that certain foods “negatively impact the microbiome due to their inflammatory properties, minimal fiber and effect on insulin.”

Inflammatory foods, which include ultra-processed snack foods, red meats and sugar-sweetened beverages, can cause imbalances in the gut microbiome that increase inflammation throughout the body. That inflammation can then elevate the risk for certain diseases, such as heart disease, or exacerbate inflammatory conditions like asthma and diabetes.

These foods can “also affect the pH of the food going through the GI tract, lowering it and making it more acidic, which can harm the microbiome,” Hunnes says. They can raise blood sugar levels, as well, which can impact insulin down the line.

Eating for good gut health means eating to support the multitude of healthy bacteria that live in the gut — and avoiding some foods, especially those that cause inflammation or affect insulin, like extra sugary items.

Foods to avoid

While there are plenty of things you can eat to support good gut health, there are also some foods you should limit.

“An excessive intake of added sugar and saturated fats has been shown to create an imbalance within the microbiome, often referred to as ‘dysbiosis’ in the gut,” explains Jennifer McManus, a registered dietitian and certified diabetes care and education specialist with Pendulum Therapeutics, a probiotics company based in San Francisco.

Dysbiosis, according to a 2019 study in Scientific Reports, is “a loss or gain of bacteria that (promotes either) health or disease, respectively.”

It can lead to chronic inflammation, which in turn often precedes the development of metabolic diseases, such as diabetes, obesity and heart disease. If you’re looking to support good gut health, there are certain foods you should limit or avoid. The following seven foods have been shown to potentially damage gut health.

1. Sugary foods and drinks

Excess sugar is one of the worst offenders for gut health. A 2018 study in the journal Nutrients found that mice fed a diet high in excess sugar experienced an alteration in the makeup of their gut microbiome as well as increased gut permeability (so-called leaky gut) and increased inflammation. This in turn increased rates of fatty liver disease.

Sugary drinks, in particular, are bad for gut health, according to research published in 2019 in JAMA Internal Medicine. The findings suggest that consuming higher levels of total soft drinks, including sugar-sweetened and artificially sweetened soft drinks, is associated with deaths from digestive diseases.

2. Artificial sweeteners

So, if sugar is harmful to gut health, artificial sweeteners should help you avoid that problem, right? Not so fast. Artificial sweeteners are another of the biggest culprits in poor gut health.

An array of artificial sweeteners pass through the body undigested, which means they can negatively affect the microflora in your gut, says Lisa Jones, a registered dietitian based in Philadelphia.

Research published in April 2021 in the International Journal of Molecular Sciences suggests that consuming artificial sweeteners aspartame, saccharin and sucralose may be associated with two harmful gut bacteria, E.coli and E. faecalis.

A 2018 study in the journal Molecules reports that the consumption of artificial sweeteners has been linked with an array of adverse effects, including a negative change in gut microbiome activity.

Common artificial sweeteners include:

— Stevia. Available under various brand names, such as Splenda Naturals Stevia Sweetener and Truvia.

— Aspartame, brand name Equal.

— Sucralose, brand name Splenda.

— Saccharin, brand name Sweet’N Low and Necta Sweet.

— Acesulfame, or Ace-K, brand name Sunett.

3. Alcoholic beverages

The federal government’s 2020-2025 Dietary Guidelines for Americans recommends moderate drinking for those who imbibe. That means two drinks or less a day for men and one drink or less daily for women. Drinking more alcohol than this amount can harm your gut microbiome, Jones says.

Research published in the journal Gut Microbes in 2020 suggests that drinking alcohol excessively is associated with dysbiosis. As mentioned earlier, dysbiosis occurs when the bacteria in your gastrointestinal tract — including your intestines — become unbalanced.

Dysbiosis is associated with a wide range of health problems, including:

Acid reflux.

— Acne, psoriasis and skin rashes.


— Chronic fatigue.


— Cramps.

— Diarrhea.

Digestive issues.

— Food intolerance (bloating, gas).

Trouble urinating.

— Vaginal or rectal itching or infections.

4. Fried foods

Saturated fat, a key feature of fried foods, is also hard on the gut, making these foods more difficult for your body to digest compared to fresh fruits and vegetables, Jones says. “The oils that may be used to fry the food are rich in saturated and trans fats, which can bother your gut.”

Palm and coconut oils are typically used to fry food. Eating fried foods can lead to:


— Gas.

— Stomach pain.

5. Red meat

“Diets high in red meat and fats are especially bad for gut health,” says Kim Kulp, a registered dietitian nutritionist specializing in gut health and owner of the Gut Health Connection in the San Francisco Bay Area. Fatty meats like burgers, sausage and bacon can all be problematic because “when gut microbes feed on red meat, they release an enzyme that can lead to inflammation.”

These foods are also high in L-carnitine, a compound that can alter the gut microbiome and lead to the production of a substance known as trimethylamine N-oxide, or TMAO, says Stacy Cavagnaro, a registered dietitian with Cleveland Clinic’s Center for Human Nutrition. High levels of TMAO increase your risk for heart attack or stroke.

“Diets high in red meat have also been linked to colon cancer and heart disease,” Kulp adds. “Too many high-fat foods (according to 2015 research in Current Opinion in Clinical Nutrition & Metabolic Care) can decrease the numbers of good gut bacteria while increasing those that can damage the lining of the intestines and also lead to inflammation.”

In addition, research published in 2020 in the journal Advances in Nutrition suggests that “when consumed at higher-than-recommended levels as part of a diet high in sugar or fat, beef has adverse consequences for the gut microbiota.”

Cleveland Clinic recommends eating no more than one to two servings of red meat weekly, or 6 ounces per week. People with heart disease or high cholesterol should limit their consumption to 3 ounces weekly.

6. Salty foods

Dr. Edward Salko, a family and emergency medicine specialist and the medical director of Personalabs, a direct-to-consumer lab testing and telehealth company based in Fort Myers, Florida, notes that salty foods can also be detrimental to gut health.

“Salty foods cause bloating, fluid retention, headaches and high blood pressure,” he explains. High-salt foods, he adds, can also disrupt protein digestion, which can alter how the gut microbiome functions.

What’s more, a 2019 review in the American Journal of Physiology noted that “high-sodium diets promote local and systemic tissue inflammation and impair intestinal anatomy compared with low sodium intake in both human and animal studies.”

The gut dysbiosis that results from a high-sodium diet could contribute to the development of hypertension, the study suggests.

7. Ultra-processed foods

Processed foods containing additives and salt are also on the foods-to-avoid list, Cavagnaro says. “Processed foods lack diversity and are low in fiber. Eating processed foods that contain additives and salt can affect your gut microbiome negatively.”

What’s more, certain ultra-processed foods also contain excess sugar, which can be hard on the gut.

Highly processed foods include:

— Bacon, ham, pate and sausage.

— Canned vegetables.

— Cakes.

— Cookies.

— Processed lunch meats.

— Soft drinks.

What to eat instead

Anastasia Gialouris, a registered dietitian in Brooklyn, New York, says that “to support a healthy gut, we need to support our probiotics, which are actual, live, health-promoting bacteria that inhabit the gut.”

This diverse population of good bacteria love to chomp down on fiber, “a nutrient that’s primarily found in plants,” Gialouris says. She recommends “aiming for a balanced diet rich in a variety of fruits, vegetables and whole grains.”

Prebiotics are plant fibers that the healthy bacteria in the gut feed on. Adding more prebiotic foods can help ensure this population of bacteria thrives. Prebiotic foods include:

— Bananas, raspberries and other fruits. “The less ripe, the more prebiotic fiber they contain,” Gialouris says.

— Leeks, onions and other vegetables.

— Beans and legumes.

— Whole grains.

Probiotic foods contain strains of live, healthy bacteria that can help repopulate the gut with the right kind of microbes. Probiotic foods are typically fermented. Examples include:

— Sauerkraut.

— Yogurt.

— Kimchi.

— Miso.

— Kefir.

Consuming a healthy, balanced, plant-based diet that contains plenty of unprocessed vegetables, fruits, whole grains, nuts and seeds can support a healthy gut, Hunnes says. “(These) provide food for the microbiome that help feed the healthy bacteria. They are anti-inflammatory and high in nutrients that are healthful to the microbiome, and they do not elicit a strong insulin response. They also keep the pH of the GI tract a little more basic, meaning a higher pH level, which is better for the microbiome.”

McManus says, “Ultimately, our gut microbiome shapes our health through the prevention, development and progression of disease. It is important to take care of our gut microbiome by being mindful of what we are putting in it. Prioritizing fiber, avoiding processed foods and limiting alcohol intake will have a beneficial impact on the health of our microbiome.”

Other ways to support good gut health

Ensuring good gut health goes beyond simply the foods you eat, Hoch says. “Gut health is not only influenced by what we eat but other lifestyle factors, such as smoking, sleep quality, physical activity and mental health, like stress and anxiety.”

This means that focusing on overall health and well-being by making sure to exercise, get good rest, reduce stress and quit smoking can “do wonders for the gut.”

Drinking plenty of water can also help support a healthy digestive system, as can determining if you have food allergies or food sensitivities. Understanding whether you have a condition such as celiac disease (an inability to digest gluten) or lactose intolerance (an inability to digest certain dairy-based proteins) can help you select foods that are less likely to irritate your digestive system.

Moderation in all things

Lastly, Gialouris says that while it’s best to avoid processed foods, she doesn’t want to “scare folks into thinking they can never eat a packaged cookie or French fry again if they want to support their gut health. As a dietitian, the advice I give almost everyone, no matter the health concern, is to consistently practice health-promoting habits most of the time, but also allow themselves to occasionally eat foods that maybe aren’t the healthiest choice but bring them joy and satisfaction.”

She says this balance can make you happier and healthier. “By maintaining a healthful, plant-rich diet and enjoying the occasional treat, we can sustainably reach our health goals.”

Top worst foods and beverages for your gut health:

The worst food for your gut health include:

— Sugary foods and drinks.

— Artificial sweeteners.

— Alcoholic beverages.

— Fried foods.

— Red meat.

— Salty foods.

— Ultra-processed foods.

For good gut health, remember to:

— Have probiotic-rich food instead.

— Make lifestyle changes.

— Eat processed food in moderation.

Table of Contents

— You are what you eat.

— Your gut is home to many organisms.

— Eating for good gut health

— Foods to avoid

— 1. Sugary foods and drinks

— 2. Artificial sweeteners

— 3. Alcoholic beverages

— 4. Fried foods

— 5. Red meat

— 6. Salty foods

— 7. Ultra-processed foods

— What to eat instead

— Other ways to support good gut health

— Moderation in all things

— Top worst foods and beverages for your gut health:

More from U.S. News

7 Habits for a Healthy and Happy Life

Best Foods to Eat for an Upset Stomach

Health Issues That Are Sometimes Mistaken for Gluten Sensitivity

Worst Foods for Gut Health originally appeared on usnews.com

Update 01/18/23: This story was previously published at an earlier date and has been updated with new information.

Related Categories:

Latest News

More from WTOP

Log in to your WTOP account for notifications and alerts customized for you.

Sign up