What Are the Worst Foods for People With IBS Symptoms? A Dietitian Explains

Irritable bowel syndrome (IBS) is a chronic digestive condition that affects up to 1 in 5 people in the U.S. And IBS flare-ups can have a significant impact on someone’s quality of life. But identifying potential food triggers can help. In this article, we share the top food triggers of IBS and how to identify them in your diet. 

What is IBS?

IBS is a chronic digestive condition marked by sporadic bouts of symptoms. Common symptoms include: 

• Abdominal pain

• Bloating

• Gas

• Diarrhea and/or constipation

It’s normal for anyone to have these symptoms from time to time. But if you feel like you experience them more frequently than the average person, it might be time to talk with your primary care professional. 

First, your doctor may run diagnostic tests to rule out other digestive conditions. If the results of these tests are normal and your symptoms have been ongoing for at least 6 months, it’s possible that you may have IBS.

The specific cause of IBS remains unknown. Scientists think that there’s a genetic component. And mental health conditions — like depression, anxiety, and ongoing stress — can affect IBS symptoms. This is likely because of the brain-gut connection. But no matter what the underlying cause, experts have also identified certain foods that tend to trigger the condition. 

Which foods trigger IBS? 

There are a limited number of treatments for IBS. But identifying specific food triggers can help manage your symptoms, and improve your quality of life. Four in five people with IBS report at least one food trigger for their IBS. The following five foods are the most common culprits of IBS symptoms. 

1. High-FODMAP Foods 

FODMAPs stands for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols. The FODMAPs are a specific type of carbohydrate found in many foods that can be difficult for your body to digest and absorb. 

“FODMAPs pull water into the colon. This can cause diarrhea in someone who is prone to it. For people more prone to constipation, this can also cause bloating,” said Kristin Houts, MS, RD, a Chicago-based dietitian with a focus on gastrointestinal disorders. “Because these carbohydrates are poorly absorbed, they ferment in the colon causing excess bloating, gas, and cramping in those with IBS.”

It's important to note that the FODMAP diet has a long list of foods to limit or avoid. This means it can be overwhelming to start, and even more difficult to maintain. 

It’s recommended to work one-on-one with your gastrointestinal specialist or a registered dietitian nutritionist (RDN) if you want to modify your diet to avoid high-FODMAP foods. The goal is to reintroduce specific foods and determine which foods may be causing your symptoms. An RDN can help you personalize your diet so that you’re restricting as few foods as possible. 

It’s also important to note that a FODMAP diet is not intended to be long-term because it can cause nutritional deficiencies. 

2. Fatty foods

It’s common for people to report tummy troubles after a meal that’s high in fat. Fat — compared with protein and carbohydrates — takes longer to digest. And certain types of fat could contribute to inflammation of the intestines in people with IBS.  A high-fat meal may cause your digestive system to slow down, which can also lead to gas and bloating. 

Eating some fat with your meal is important for satiety. Fat also helps your body absorb certain nutrients in your food. Consider opting for monounsaturated and polyunsaturated sources of fats — like avocados, nuts, healthy oils, and fatty fish. To keep the amount of fat at your meal in check, make sure you’re eating a balanced meal made up of protein, carbohydrates, and some fat. 

3. Alcohol

Alcoholic beverages can exacerbate digestive symptoms. Alcohol has many effects on the body. When it comes to your gut, it relaxes the muscles that line your intestines. This can cause food to move through quicker than normal. It can also allow nutrients to flow more freely in and out. This is one of the reasons why heavy drinking can cause: 

• Diarrhea 

• Nausea 

• Stomach upset 

• Indigestion 

• Reduced absorption of nutrients (or malnutrition) 

It’s unlikely that moderate alcohol intake (less than one drink per day for women, or two drinks per day for men) will cause these symptoms. You may also find that specific types of drinks affect you more than others. 

4. Spicy food 

Curious why chili might make you run to the bathroom? It’s because of the active ingredient found in chili powder, called capsaicin. It can cause diarrhea, reflux, and burning during bowel movements in certain people.   

5. Caffeine 

Caffeinated coffee is well-known for its laxative effects. Coffee and other caffeinated beverages activate the muscles in the lower gastrointestinal tract, which can lead to a bowel movement. 

The FDA states that up to 400 mg of caffeine per day for healthy adults is safe. That is about three to five 8 oz cups. However, some people may be more sensitive — and may have a stomachache or other digestive issues — after drinking any amount of coffee.  

A few additional tips

Beyond the specific foods you eat, other factors can trigger IBS symptoms, too. Houts recommends: 

• Sticking to a regular meal schedule as much as possible

• Avoiding large meals

• Staying hydrated, since your body uses water in the digestion process

• Being mindful of your mood when you eat, since eating while stressed affects digestion

Is it lactose intolerance or IBS?

Lactose intolerance and IBS may cause similar digestive symptoms, but the cause is different. 

Lactose is a type of natural sugar found in dairy foods. It’s broken down by an enzyme called lactase so that your body can absorb it. 

As some people age, they may begin to lose their ability to produce lactase. This can lead to many of the same symptoms as IBS, like bloating and changes in bowel habits. 

How to log a food and symptom journal?

If you’re trying to figure out which foods trigger your symptoms, consider logging a food and symptom journal. Your food sensitivities are individual and unique to you. Despite what you see on social media, there are no FDA-approved tests for diagnosing food sensitivities. 

To log a food and symptom journal, all you need is a notebook and a pen (or your smartphone). For each food entry, include these details: 

• Date and time 

• Meal or snack

• Where 

• With whom

• Food or drink

• Brand and ingredient details 

• Preparation and cooking

• Quantity

You’ll also log your symptoms and bowel movements at the end of the day. For each of these entries, log: 

• Date and time 

• The symptoms you’re currently experiencing 

• Any details about your bowel movements (size, consistency, accompanying symptoms)

Houts reminds that “something you just ate is unlikely to be the sole contributor to a flare up in your symptoms. Digestion can be a longer process than we realize. This means that something that you ate yesterday might actually be playing a role.”

This is why a food journal can be a helpful tool to recognize patterns in how certain foods affect your IBS symptoms.

Why trust our experts?

Written by:

Kerry Hackworth, MS, RD, LDN

Kerry Hackworth has been in the field of nutrition for over a decade. Her career began in corporate wellness, where she provided personalized health coaching.

Edited by:

Katie E. Golden, MD

Katie E. Golden, MD, is a board-certified emergency medicine physician and a medical editor at GoodRx.

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