What are the worst foods for gut health?

Key Points

• The foods we eat can impact our gut microbiome.
• Foods high in sugar, salt and saturated fats can have a negative impact.
• Eating more fibre and a variety of whole foods can help.

The gut has been given a lot of good press lately, and deservedly so. Heralded as the ‘second brain’, our gut matters, so bettering our gut health has never been more vital.

By now, many of us know at least a little about probiotics, prebiotics and the foods we need to eat to support our GI system. But what about the worst foods for gut health? Are certain things we eat or drink possibly throwing our hard work out of whack?

Our gutmicrobiome is shaped by what we eat, so eating more or less of certain foods can make a difference. In this article, we’ll uncover the best and worst foods for gut health, giving you an easy way to support a healthier body and mind through the power of your gut.

Bad foods for gut health

A closer inspection of the foods we eat is crucial in our quest toward a healthier gut. 

Among the worst foods for gut health are those high in sugar, salt and saturated fats. Many of the foods found in the discretionary food list — like processed meats, deep-fried foods, pastries and cakes — can cause an imbalance in gut bacteria.

We spoke to Accredited Practising Dietitian Kate Agnew to find out why. “Refined and highly processed grains contain fewer important nutrients, particularly fibre,” she says.

Among its other health benefits, fibre provides the food needed to feed the good bacteria in our gut, while high-fibre foods can also support a healthier digestive system. Adding more fibre to your diet and being mindful of your intake of the kinds of foods that can upset the balance of your gut bacteria may help improve gut health.

What about alcohol?

Many of us enjoy a responsible drink now and then. But if you’re not mindful, alcohol could be one of the worst things for gut health. “Alcohol has been shown to affect the gut microbiome and the balance of gut bugs,” says Kate. Furthermore, studies have shown that alcohol can act as a gut irritant for some individuals.

Sometimes the link between alcohol and gut health can be muddied as people hear about its potential health benefits, for example, the resveratrol content of red wine.

However, Kate urges caution: “While some classes of alcohol have beneficial compounds, the impact of alcohol on the gut far outweighs them. Additionally, we can achieve these beneficial compounds by eating other whole foods, like grapes.”

Which meats are worse for gut health?

As meat holds a special place on many of our dinner plates, we want to ensure we’re eating it in the proper form. For our gastrointestinal (GI) system, some types of meat may be foods bad for gut health, whereas others might be better.

Aiming to avoid processed meats where possible is usually a good idea. Studies have shown that processed foods typical of a Western diet can cause an imbalance in the gut system. Therefore, consider eating meats like deli meats, bacon and hot dogs only in moderation. 

On the other end of the spectrum,, we should aim to eat more lean meats, poultry and fish. “It’s good to eat a variety of animal protein and mix it up with lean meat, chicken, fish and eggs,” says Kate.

“Additionally, amino acids — the building blocks of animal protein — have been shown to contribute to maintaining the gut mucosa. So the protein quality is just as important.”

Finding a happy balance

The Australian dietary guidelines recommend a maximum of seven serves of lean red meat each week. The average adult should eat one to three servings daily from the lean meat/poultry, fish, eggs, tofu, nuts/seeds and legumes/beans group.

According to studies, a diverse diet, including plant-based foods, has been linked to a healthier gut microbiome. A US-based project on gut health found that eating at least 30 plant foods a week was recommended for better health outcomes. Eating more plant-based foods, including the best fruit for gut health, can help.

A balanced diet with foods from all five food groups is essential for meeting your nutritional requirements.

Are FODMAPs the worst things for gut health?

FODMAPs are sometimes given a bad rap as foods bad for your gut health. The truth is, they can be anything but. FODMAP is an acronym representing six groups of sugars found in healthy and unhealthy foods. For sufferers of IBS, eating certain high-FODMAP foods can exacerbate gastrointestinal symptoms.

Healthcare professionals may recommend this restrictive diet for several weeks, eating only from the low-FODMAP food list. Foods are reintroduced gradually from each FODMAP group to determine which components are causing symptoms. However, it doesn’t necessarily mean that these are unhealthy foods.

“FODMAPs are found in many foods we eat and, for individuals without gut symptoms, are responsible for many health benefits because they feed the bacteria in our gut,” says Kate. For example: are bananas good for gut health? Yes. But in their ripe state, they’re considered a high-FODMAP food.

Should you follow the FODMAP diet?

There are usually no benefits to giving up high-FODMAP foods unless you’ve been advised to by your healthcare professional.

“Most people can tolerate small amounts of high-FODMAP foods, and we know that including these foods can greatly benefit our gut microbiome,” says Kate.

Additionally, following a low-FODMAP diet has been shown to decrease the number of good bacteria in our gut. The solution? To eat a diet consisting of high- and low-FODMAP foods in order to support a healthier gut system.

Does an air fryer help?

Although we may find them tasty, fried foods have some downsides. One study showed that fried foods may contribute to inflammation in the intestine. Another found that consuming fried meat lowered the microbial community richness within the gut.

So, in hopes of turning bad gut health foods into good ones, you might have considered reaching for the air fryer. But can it have a positive impact? Without enough research, the jury is still out on these new appliances.

“Most foods we place in air fryers are processed, which we know may have a negative impact on  gut health,” says Kate. Instead, she recommends some healthier strategies when using your air fryer. Some examples include using wholegrain breadcrumbs, cooking with quality extra virgin olive oil and making chips with fresh potatoes.

Supporting a healthier gut

The more we learn about the importance of good gut health, the more we can support it. Knowing more about the worst foods for gut health can help us eat those foods in moderation while also ensuring we eat more of the good stuff.

If you’re experiencing GI symptoms or want to learn more about gut health, speak to your healthcare professional.

Related:

• How to increase the good bacteria in your gut naturally
• Gut health foods: 4 of the best
• Understanding gut dysbiosis

Kate Agnew is an Accredited Practising Dietitian who is passionate about innovation and problem-solving in health & nutrition. Her goal is to ultimately create a healthier environment for all Australians.

Reviewed by healthylife health experts January 2023.