Here's How the Low FODMAP Diet Helps Treat IBS

Tummy *always* upset? This eating plan might help.

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A frustrating part of irritable bowel syndrome (IBS) is that it can’t really be treated—only managed through careful and deliberate lifestyle changes. Eating small and frequent meals, limiting certain foods, and managing stress can all improve IBS symptoms.  

But an even more frustrating part of IBS is that the foods that trigger IBS symptoms are not so clear. A food can cause a riot in your colon one day, and be perfectly fine the next. As you try to figure out what’s “safe” and what’s not, each meal can feel like walking through a minefield.

Enter: The low FODMAP diet. This dietary plan “helps manage symptoms of digestive distress—gas, bloating, pain, and alteration in bowel habit,” says Kate Scarlata, RDN, LDN, and author of The Low-FODMAP Diet Step by Step.

What FODMAPs Actually Are

The term “FODMAP” is actually an acronym for a group of short-chain carbohydrates that tend to spell trouble for those with IBS. These carbs aren’t dangerous or unhealthy, they “are fast food for our gut microbes who eat them readily and create copious gas,” explains Scarlata. They pull water into the gut, and “the gas and water stretch the intestine and lead to cramping and pain,” but usually only for those with a sensitive gut.

The names of these carb categories create the acronym FODMAP: 

  • Fermentable Oligosaccharides,

  • Disaccharides,

  • Monosaccharides,

  • And Polyols.

Hang on—don’t get intimidated yet. The crazy names don’t really matter, and you don’t need to be able to spell the names to be able to successfully implement the low FODMAP diet, which was developed by researchers in Australia and has even been adopted into the National Therapeutic Guidelines there.

Here’s how it works: “The low FODMAP diet is a 3-phase diet,” says Scarlata. “[It] starts with the elimination phase where all high FODMAP foods are eliminated.” (It’s similar to doing an elimination diet to test for food allergies.)

Next, high-FODMAP foods are systematically reintroduced to the diet, one at a time. During this time, you take careful note of which foods trigger symptoms and which do not.

Finally, the third and final phase is the personalization phase, “when tolerated FODMAPs are gently added back onto the plate to the individual’s tolerance,” says Scarlata. The goal is to be able to enjoy as “varied a diet as possible” while also managing symptoms, she says.

What *Not* to Eat on a Low FODMAP Diet

Nothing is necessarily “off limits” on a low FODMAP diet, and it’s tailored to the individual and what their gut can handle. One person with IBS may be able to handle a certain food with no problems, while another can’t handle it at all, while yet another can only handle it in small amounts.

That said, here are examples of each type of short-chain carbohydrate that is avoided during the elimination phase: 

  • Fermentable oligosaccharides: These include wheat, onion, garlic, and kidney beans.

  • Disaccharides: This includes all dairy products: milk, ice cream, cheese, etc.

  • Monosaccharides: These include “natural sugars” and fruit, such as watermelon, honey, and mango.

  • Polyols: These are known as “sugar alcohols,” which can be found naturally in foods or added into “sugar-free” products like candy and gum. Foods with naturally-occurring polyols include apples, peaches, plums, and cauliflower.

To be clear, this is *not* a comprehensive list, and you should work with a professional trained in the low FODMAP diet if you wish to try it.

What to Eat on a Low FODMAP Diet 

Well, the short answer is “whatever is not on the list or whatever your gut is okay with.”

Here are some of the foods that tend to be safe for people who can’t properly digest FODMAPs:

  • Gluten-free grains, like oatmeal, quinoa, corn, and rice.

  • Low-fat meats

  • Eggs

  • Non-dairy alternatives, like oat milk and almond yogurt

  • Certain fruits and vegetables, like bell pepper, carrots, potatoes, oranges, strawberries 

So, What’s the Big Deal with the Low FODMAP Diet?

To be clear, the low FODMAP diet is *not* a weight-loss diet. It has one goal: To calm the angry bellies of people with IBS. And that’s a big deal since IBS has been historically difficult to treat. 

“Scientific research shows it manages these often debilitating symptoms in IBS in up to 50 to 70 percent of those who suffer with this condition,” says Scarlata. “Other studies have shown that it can help reduce digestive symptoms in patients with inflammatory bowel disease.”

“Emerging science shows that it may help endurance athletes as well—as many runners are prone to diarrhea,” says Scarlata.

OK, So What’s the Catch with the Low FODMAP Diet?

You’ve probably noticed by now, but the low FODMAP diet is really complicated, personalized, and requires a lot of guess-and-check work, food journaling, and visits with a qualified dietitian. It’s not something you can just casually try out and expect to get meaningful results. 

The low FODMAP diet tends to be effective when done right, but the most common reason it fails is because the person simply gives up. That’s a major drawback in a society that favors quick fixes.

And of course, the low FODMAP diet can cut out some legit healthy foods, like apples, whole wheat, and garlic. While nobody should eat food that causes them severe pain, the International Foundation for Functional Gastrointestinal Disorders stresses that this approach is a low FODMAP diet, not a no FODMAP diet.

 Should You Try the Low FODMAP Diet?

If you’re having trouble managing your IBS symptoms, then the low FODMAP diet might be a good approach to try. It can empower you to understand why certain foods might be triggering symptoms and how to assemble a meal that won’t upset your colon so much. 

… Just make sure you’ve got a trusted nutritionist to guide you.