What Is a FODMAP?

Healthy Living

March 25, 2021

If your intestines seem continually plagued by gas, constipation, diarrhea or bloating, you might be willing to do whatever it takes to fix the problem. For some people, trying a low FODMAP diet can be the key to finding relief from these troublesome symptoms.

This strict elimination diet can be a challenge, but it’s not one that will last forever. 

Rather, a short period of restrictive eating could help you identify which foods you can and can’t eat. Once you know your triggers, you can develop a personalized long-term plan for well-balanced eating and bowel health.

Note: the following is for information only and shouldn’t be used to diagnose or treat any medical condition. Always talk to your doctor if you have questions about your health.

Understanding FODMAPs

The acronym FODMAP stands for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols. 

That’s a complicated name, but it refers to several categories of sugars that are naturally present in many foods. These particular sugars share a few key characteristics:

  • Osmotic: They draw water into the small intestine.
  • Fermentable: They can be fermented by bacteria in the large intestine, and that process produces gas.

Lots of foods have FODMAPs to varying degrees, including many of the things you might toss in your grocery cart each week. Examples include apples, yogurt, bread, honey, onions and ice cream.

Trouble with FODMAPs

These sugars take their time moving through your intestines. As they do, they draw in water and undergo fermentation.

For some people, that’s no big deal. They eat FODMAP-rich foods without any significant side effects. 

But people with irritable bowel syndrome (IBS) aren’t so lucky. For IBS sufferers, the water and gas that FODMAPs add to the colon may alter the size and shape of the intestinal wall. 

As a result, FODMAP sensitivity can lead to symptoms like bloating, cramping, flatulence, constipation and diarrhea.

The Low FODMAP Diet

Living with IBS may be easier if you can figure out which foods trigger your symptoms.

Researchers at Monash University in Australia developed the low FODMAP diet to help people identify which foods cause them intestinal distress. It seems to work, too. According to their research, this approach helps around 75% of people with IBS.

A low FODMAP diet isn’t a long-term lifestyle. Instead, it’s a short-term elimination diet designed to identify the foods that cause you the most trouble.

  • Step 1: Remove foods that are high in FODMAPs from your diet for a set period of time.
  • Step 2: Reintroduce these foods one at a time and watch for IBS symptoms.

The elimination portion of your eating plan should last for at least two weeks but no more than six. During this time, you should cut out items that are high in FODMAPs and plan your meals and snacks around foods with low levels of these sugars.

The reintroduction phase may last 8 to 12 weeks. You can add one food back into your diet every three days. It’s smart to keep a journal during this phase to record symptoms that you experience after eating various foods.

There’s no easy way to look at a food and know it contains high (or low) amounts of FODMAPs. It’s something you’ll pick up over time. 

But there are apps you can download — like this handy one from Monash University — to help you identify safe and not-so-safe options while you’re in the elimination phase.

Starting a Low FODMAP Diet

The low FODMAP diet isn’t easy, and it’s not something to take on without the guidance of a doctor. It will involve major lifestyle changes. There’s no point in starting an elimination diet that’s as specific as the low FODMAP one without talking to a doctor about your symptoms first.

Plus, you’ll need to make sure you actually have IBS or another condition that would benefit from this elimination diet.

Abdominal pain or bloating, particularly before or after bowel movements, is one sign that you should schedule an appointment to discuss IBS. Increased gas or changes in the frequency or consistency of your bowel movements may also point to IBS.

But abdominal pain and related symptoms might not be caused by IBS at all. You may have something else going on, such a food allergy or any number of other health conditions, so start with your doctor to rule out other issues.

Once you get a diagnosis, the Monash University FODMAP team recommends trying an elimination diet as a first strategy. For this, it’s best to find a registered dietitian (RD), particularly one with experience in the field of IBS and other gastrointestinal conditions. 

An RD can help you determine which foods to eliminate and how to add them back into your diet. Working with a nutrition professional is especially important if you’re underweight.

That’s because the list of items that you’ll need to avoid during the elimination portion of the diet will be extensive. 

Examples of high FODMAP foods include:

  • Certain fruits, like apples, cherries and pears
  • Certain vegetables, like garlic, broccoli, onions and cauliflower
  • Wheat products and products containing wheat
  • Legumes, like lentils and chickpeas
  • Lactose-containing dairy products, like milk and cream
  • Some sweeteners, like honey, high fructose corn syrup and xylitol

As we mentioned earlier, the Monash FODMAP app comes in handy during the elimination phase. It rates foods as low, moderate or high in FODMAPs based on serving size, so it takes away some of the guesswork. Note that this app isn’t free, but it might be worth the cost to ease some of your frustration at the outset.

Life After an Elimination Diet

The goal of a low FODMAP diet isn’t to keep every high FODMAP food out of your life forever. It’s to figure out which foods cause you grief. 

In fact, there’s a good chance that you can tolerate some sugar categories and some foods better than others. And even some of the foods you can’t tolerate might be okay in smaller portions.

That’s the point of this diet, to figure out what does and doesn’t work for you.

By reintroducing food groups one at a time, you can note which ones trigger IBS symptoms (and to what degree). Those are the foods that you’ll want to reduce or eliminate from your regular diet.

The ones that don’t cause you trouble can stick around. 

It’s a smarter approach than cutting them all out for good. Many foods that are high in FODMAPs contain good-for-you nutrients, including vitamins, minerals and fiber. Also, research indicates that following a restrictive FODMAP diet over the long haul may have a negative effect on the amount of beneficial bacteria in your digestive tract.

Keep in mind, too, that not all fruits, vegetables and grains are high in FODMAPs. You can learn to substitute low FODMAP alternatives for the foods that do trigger you.

  • Eat oranges, unripe bananas and grapes instead of apples and cherries.
  • Swap carrots, potatoes and lettuce for broccoli and asparagus.
  • Use the tips of green onions (the green part) instead of regular whole onions.
  • Try rice pasta instead of wheat pasta.
  • Get your protein from meat, poultry, fish and eggs instead of beans and other legumes.

Other therapies

While a low FODMAP diet can help many IBS sufferers, it’s possible that you won’t respond as well to it, or you may need additional therapies. 

Some people’s symptoms improve with over-the-counter or prescription medications that can relieve constipation, reduce diarrhea, calm bowel spasms or improve gut bacteria levels. 

You may also notice some improvement if you exercise regularly, take probiotics or practice stress reduction. Your doctor can help you identify therapies that may work for you.

Irritable bowel syndrome can reduce your quality of life and leave you miserable. Although a FODMAP elimination diet can seem like an extreme and burdensome step, it may lead to a healthier, happier life with a diet built around foods that don’t irritate your belly.