Here’s What You Should Know About Low and High FODMAP Foods

Digestive distress is no fun, and if you suffer from it, you’re hardly alone.

According to the American Gastroenterological Association (AGA), 60-70 million Americans suffer from GI issues that can seriously impact their quality of life. AGA’s data shows that nearly 40% of Americans have stopped routine activities in the last year due to annoying, uncomfortable, and – in some cases – debilitating symptoms.

Digestive symptoms aren’t always easy to treat because they’re so diverse and manifest differently in different people. They range from relatively common symptoms like bloating and gas, to much more serious ones like blood in the stool. To further complicate matters, many symptoms can be consistent with a wide range of possible causes, ranging from minor food intolerances to colorectal complications.

What’s more, these symptoms aren’t easy to talk about. One in three people said they would only discuss their bowel symptoms if their doctor brought it up first. The AGA recently launched an awareness campaign called Trust Your Gut, aimed at shortening the time between having bowel symptoms and actually talking about them with your doctor.

This article isn’t about GI health in general – that would take a book to discuss adequately. But it is about a particular intervention that many have found helpful (at least in the short-term).

That intervention is a low-FODMAP diet.

Bacteria and Your Gut

To understand why some health practitioners recommend low-FODMAP diets (don’t worry, I’ll define what they are shortly), it’s helpful to understand something about bacteria and your gut.

The human body has about 30 trillion cells, but we also host trillions of non-human cells as well. The most current research estimates that there are 39 of these non-human cells (viruses, bacteria, fungi, and other assorted microbes), about 1.3 times the number of human ones. The name scientists give for that group of microbes is the microbiome, and it’s been an exploding topic of research for over a decade.

The cells of the microbiome live mainly in the gut, specifically in the large intestine. Many articles and books have been devoted to explaining how important the health of the microbiome is and detailing ways that we humans can keep it healthy. In fact, the health of the microbiome has been linked to many serious health conditions.

But sometimes microbes get into places they don’t belong, for example, the small intestine. If bacteria that doesn’t belong gets into the small intestine and starts to set up shop there, digestive symptoms almost always appear. In fact, there’s now a name for this condition: it’s called SIBO which stands for small intestine bacterial overgrowth.

And it can be maddening.

Enter low-FODMAP diets.

What Are FODMAPs and Should I Eat Low or High FODMAP Foods?

Low-FODMAP diets have been found to relieve symptoms of both SIBO and IBS (irritable bowel syndrome).

FODMAP stands for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (for those who like to nerd out, saccharides are sugars and polyols are sugar alcohols). Foods that contain these compounds are believed to act as prebiotics, which means they “feed” the bacteria that set up residence in the small intestine. A low-FODMAP diet is essentially a symptom-reduction strategy based on starving them out!

But there are a couple of problems and cautions.

Problem #1: Foods that contain FODMAPs are not bad foods, at least not always. In fact, some of them – like, for example, onions and garlic – are extraordinarily healthy foods. Their only “crime” is to provide food for bacteria that we want to get rid of (or at least remove from the small intestine).

This is one reason low-FODMAP diets aren’t recommended long-term. The foods that contain FODMAPs may indeed feed the bacteria in the small intestine, but they also provide nourishment to the “good guy” bacteria in the large intestine, which is why you don’t want to keep them out of your diet forever. At least two studies have demonstrated that being on a long-term, low-FODMAP diet can reduce the levels of beneficial bacteria in the gut (colon).

Problem #2: There are an awful lot of foods that contain FODMAPs. Patients put on these diets often say, “There’s nothing left to eat!” which isn’t quite true – but it’s easy to see how people could feel that way.

That said, a low-FODMAP diet does offer symptom relief in the short term, and most practitioners will begin to reintroduce FODMAP-containing foods once symptoms are alleviated.

Johns Hopkins Medicine characterizes a low-FODMAP diet as a three-step elimination diet:

  • The first step is eliminating foods high in FODMAPs (see accompanying list). This phase is recommended for between 2-6 weeks max.
  • Then start slowly reintroducing these foods, usually one at a time, and observe carefully which ones are problematic for you.
  • Finally, avoid the ones that cause symptoms and go back to eating those that don’t.

Symptoms that typically improve on a low-FODMAP diet include cramping, gas, flatulence, bloating, and diarrhea.

In one study, low-FODMAP diets reduced the severity of symptoms in over 75% of patients with IBS (compared to a 54% reduction in patients receiving standard dietary advice). Functional medicine expert Chris Kressler, LaC, reports that he’s found low-FODMAP diets to be useful in patients with Crohn’s disease, ulcerative colitis, and diverticulosis.

What About Fiber?

One of the most common issues on a low FODMAP diet is the fact that so many of the restricted foods are important sources of fiber. So, how does a person on a low-FODMAP plan supplement their fiber intake without producing the very symptoms we’re trying to get rid of, like bloating and gas?

Fortunately, there’s an easy solution to this problem: partially hydrolyzed guar gum fiber, which is found in hundreds of supplements and food products and doesn’t cause bloating or gas. You can buy it in the store or online under the name SunFiber, which was the first prebiotic soluble fiber supplement to be low-FODMAP diet approved by Monash University.

Foods that are typically restricted are wheat, beans, onions, garlic and milk; they’re typically replaced with low-FODMAP alternatives such as potatoes, rice, zucchini, and lactose-free dairy.

Though the complete list of foods high in FODMAPS is dauntingly long, Johns Hopkins Medicine sums up the most important foods to avoid:

  • Dairy-based milk, yogurt, and ice cream
  • Wheat-based products such as cereal, bread, and crackers
  • Beans and lentils
  • Some vegetables, such as artichokes, asparagus, onions, and garlic
  • Some fruits, such as apples, cherries, pears, and peaches

Fodmap Foods 2 Instead, they suggest you base your meals around low FODMAP foods such as:

  • Eggs and meat
  • Certain cheeses such as brie, Camembert, cheddar, and feta
  • Almond milk
  • Grains like rice, quinoa, and oats
  • Vegetables like eggplant, potatoes, tomatoes, cucumbers, and zucchini
  • Fruits such as grapes, oranges, strawberries, blueberries, and pineapple

Note that wheat is eliminated not because of gluten, but because wheat is high in fructans, a member of the oligosaccharide family. Nonetheless, it’s probably a good idea to eliminate gluten in general during the restrictive phase of the diet, as gluten can be inflammatory for many people.

The good news is that once you reintroduce one or two members of a category of FODMAPs (like fructooligosacchardies for example) and find that everything’s okay, you can usually reintroduce all the other members of that particular category of foods without testing each of them. Then you can move on to the next category.

Though you can do a low-FODMAP diet on your own, it’s a great idea to do it under the guidance of a nutritionist or nutritionally educated health professional.

Eliminating all these foods can be complicated and challenging, and identifying the ones that are causing symptoms can be a bit of a task. A health professional who specializes in gut and digestive issues can be your best friend during this period.

Low-FODMAP Diets and Sugar

Perhaps surprisingly, many common sugars (including cane sugar, raw sugar, and brown sugar,) are low FODMAP. That, however, doesn’t make them healthy. Though they may not trigger symptoms directly, they still raise blood sugar and insulin and can cause metabolic havoc.

There is, however, one little-known sugar that is low-FODMAP diet certified: allulose.

Allulose is considered a “rare sugar” – it exists in nature and is found in figs, raisins, and molasses, among other foods. There is a ton of published research on allulose, and it’s endorsed by many of the leading lights in the field of metabolic health, including Drs. Benjamin Britten and David Perlmutter.

Allulose doesn’t raise blood sugar or insulin, and has been shown in research to lower both insulin resistance and blood sugar.

It’s available in stores all over the country. Look for allSweet on the ingredient label.


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