Processed Foods and IBS

Irritable bowel syndrome (IBS) can cause symptoms like belly pain, bloating, diarrhea, and constipation. Experts have found several possible causes of IBS, and it may have different causes in different people. But 1 thing is for sure: What you eat can have a big impact on your IBS symptoms. For example, eating processed foods may trigger or worsen symptoms in some people.^1-4

What are processed foods?

In general, a processed food is a food that has been changed from its natural state. It may come in a package, and it may contain lots of added ingredients. Common added ingredients are:^5,6

• Salt
• Sugar
• Oils

If a food has only these added ingredients and has not changed much from its original form, it is considered minimally processed.^5,6

Sometimes, processed foods include colors or chemicals that have been added to increase flavor, texture, or shelf life. Foods that contain these ingredients are considered ultra-processed foods. So are foods that have undergone extreme change from their original form.^5,6

Minimal processing may be necessary to help foods stay fresh until people can eat them. And sometimes, helpful nutrients are added to processed foods. But overall, health experts consider processed foods to be less healthy and nutritional than natural, whole foods. Ultra-processed foods are even less healthy. They can cause weight gain and inflammation, leading to a range of health problems.^5,6

What are some examples of processed foods?

Minimally processed foods often include:^5,6

• Canned or frozen fruit
• Canned vegetables
• Canned fish
• Freshly made bread

Ultra-processed foods often include:^5,6

• Frozen meals
• Fried foods, like chicken nuggets and fish sticks
• Hot dogs and lunch meats
• Chips and other bagged snacks
• Sweetened cereals
• Packaged cookies
• Sodas
• Fruit juices made with high-fructose corn syrup

How do processed foods affect IBS?

Each person with IBS has unique triggers. For some people, processed foods are an IBS trigger. One possible reason is that food additives like artificial sweeteners, thickeners, and preservatives can upset the balance of bacteria and other microorganisms in the gut. The collection of microorganisms in each person’s digestive tract is called their gut microbiome.^3,4

The gut microbiome has wide-reaching effects on the body, including regulating certain inflammatory processes. An unhealthy balance of organisms in this microbiome is called dysbiosis. Research suggests that dysbiosis can trigger inflammation and change how quickly the body digests food (motility time). Both of these effects can lead to IBS symptoms.^3,4

One 2024 study found a link between the amount of ultra-processed foods people ate and their risk of developing IBS. In the study, the people who ate the highest amount of ultra-processed foods had a 20 percent higher risk for IBS than those who ate the lowest amount.⁴

Interestingly, this link was found only in people who drank alcohol. More research is needed on how alcohol may affect the relationship between processed foods and IBS.⁴

How to reduce processed foods in your diet

Some research shows that nearly 60 percent of calories in the typical US diet come from ultra-processed foods. This is bad news for everyone who wants to stay healthy, including those living with IBS. Eating ultra-processed foods often or in large amounts increases your risk of developing:^5,6

• Obesity
• Heart disease
• Type 2 diabetes

However, there are ways to avoid these foods. Here are some ideas:

Read food labels

In general, the longer the list of ingredients on a food label is, the more processed the food is. Try to stick to foods with just a few ingredients. Avoid foods with lots of added sugars, salts, or fats. And if you do not recognize the name of an ingredient, it is likely an additive.^5,6

Buy whole foods

Another good guideline is to do most of your grocery shopping around the outside rim of the grocery store. This is where you will find whole fruits and vegetables, as well as fresh dairy, eggs, and meats. These foods often come straight from their source with very little processing.^5,6

Make your own meals

Experts suggest eating fewer prepackaged meals. This can be hard, especially if you are short on time. But there are simple meals you can make at home that are much healthier and and easy on your stomach than a premade meal.^5,6

Recommended diets for IBS

Doctors often recommend that people with IBS change their diet in a few general ways. These will not work for everyone. The best eating plan for you will depend on the type of IBS you have and your specific triggers. But here are a few things to try:^7-9

Eat more fiber

Fiber can make stool easier to pass and may help improve both constipation and diarrhea symptoms. Experts recommend focusing on soluble fiber, which comes from food sources like beans, peas, oats, and fruits. You can also get more fiber through supplements such as psyllium seed husks.^7-9

Avoid gluten

Some people with IBS are sensitive to gluten. You can try avoiding it for a few weeks and then see what happens when you add it back in. Gluten is found in foods that contain:^7-9

• Wheat
• Barley
• Rye

Try the low FODMAP diet

FODMAP is an acronym that refers to certain types of carbohydrates (or “carbs”) that our bodies cannot process. Lots of research has shown that people with IBS can benefit from removing FODMAPs from their diet for a while. FODMAPs naturally occur in many whole foods, like certain fruits and dairy products. They also are often added to processed foods to make them:^7-9

• Sweeter
• Thicker
• More flavorful

Eating processed foods may not trigger your IBS symptoms. But cutting back on processed foods, especially ultra-processed foods, will benefit your overall health. You might even find that eating more whole foods and fewer processed foods helps you manage your IBS better.^3-6