Since what you eat can have a major effect on your body, digestive issues are incredibly common.

FODMAPs are types of carbohydrates found in certain foods, including wheat and beans.

Studies have shown strong links between FODMAPs and digestive symptoms like gas, bloating, stomach pain, diarrhea and constipation.

Low-FODMAP diets can provide remarkable benefits for many people with common digestive disorders.

This article provides a detailed beginner’s guide to FODMAPs and low-FODMAP diets.

FODMAP stands for "fermentable oligo-, di-, mono-saccharides and polyols" (1).

These are short-chain carbs that are resistant to digestion. Instead of being absorbed into your bloodstream, they reach the far end of your intestine where most of your gut bacteria reside.

Your gut bacteria then use these carbs for fuel, producing hydrogen gas and causing digestive symptoms in sensitive individuals.

FODMAPs also draw liquid into your intestine, which may cause diarrhea.

Although not everyone is sensitive to FODMAPs, this is very common among people with irritable bowel syndrome (IBS) (2).

Common FODMAPs include:

  • Fructose: A simple sugar found in many fruits and vegetables that also makes up the structure of table sugar and most added sugars.
  • Lactose: A carbohydrate found in dairy products like milk.
  • Fructans: Found in many foods, including grains like wheat, spelt, rye and barley.
  • Galactans: Found in large amounts in legumes.
  • Polyols: Sugar alcohols like xylitol, sorbitol, maltitol and mannitol. They are found in some fruits and vegetables and often used as sweeteners.
Summary FODMAP stands for "fermentable oligo-, di-, mono-saccharides and polyols." These are small carbs that many people cannot digest — particularly those with irritable bowel syndrome (IBS).

The majority of FODMAPs pass through most of your intestine unchanged. They’re completely resistant to digestion and are categorized as a dietary fiber.

But some carbs function like FODMAPs only in some individuals. These include lactose and fructose.

General sensitivity to these carbs also differs between people. In fact, scientists believe that they contribute to digestive problems like IBS.

When FODMAPs reach your colon, they get fermented and used as fuel by gut bacteria.

The same happens when dietary fibers feed your friendly gut bacteria, which leads to various health benefits.

However, the friendly bacteria tend to produce methane, whereas the bacteria that feed on FODMAPs produce hydrogen, another type of gas, which may lead to gas, bloating, stomach cramps, pain and constipation. (3).

Many of these symptoms are caused by distention of the gut, which can also make your stomach look bigger (4).

FODMAPs are also osmotically active, which means that they can draw water into your intestine and contribute to diarrhea.

Summary In some individuals, FODMAPs are poorly digested, so they end up reaching the colon. They draw water into the intestine and get fermented by hydrogen-producing gut bacteria.

The low-FODMAP diet has mostly been studied in patients with irritable bowel syndrome (IBS).

This is a common digestive disorder that includes symptoms like gas, bloating, stomach cramps, diarrhea and constipation.

About 14% of people in the US have IBS — most of them undiagnosed (5).

IBS has no well-defined cause, but it is well known that diet can have a significant effect. Stress can also be a major contributor (6, 7, 8).

According to some research, about 75% of people with IBS can benefit from a low-FODMAP diet (9, 10).

In many cases, they experience major reductions in symptoms and impressive improvements in quality of life (11).

A low-FODMAP diet may also be beneficial for other functional gastrointestinal disorders (FGID) — a term that encompasses various digestive problems (1).

In addition, some evidence suggests that it can be useful for people with inflammatory bowel diseases (IBD) like Crohn's disease and ulcerative colitis (12).

If you are intolerant, then the benefits of a low-FODMAP diet may include (9, 10):

  • Less gas
  • Less bloating
  • Less diarrhea
  • Less constipation
  • Less stomach pain

It may also cause positive psychological benefits, as these digestive disturbances are known to cause stress and are strongly linked to mental disorders like anxiety and depression (13).

Summary The low-FODMAP diet can improve symptoms and quality of life in many people with irritable bowel syndrome (IBS). It also reduces symptoms of various other digestive disorders.

Here is a list of some common foods and ingredients that are high in FODMAPs (1, 14):

  • Fruits: Apples, applesauce, apricots, blackberries, boysenberries, cherries, canned fruit, dates, figs, pears, peaches, watermelon
  • Sweeteners: Fructose, honey, high fructose corn syrup, xylitol, mannitol, maltitol, sorbitol
  • Dairy products: Milk (from cows, goats and sheep), ice cream, most yogurts, sour cream, soft and fresh cheeses (cottage, ricotta, etc) and whey protein supplements
  • Vegetables: Artichokes, asparagus, broccoli, beetroot, Brussels sprouts, cabbage, cauliflower, garlic, fennel, leeks, mushrooms, okra, onions, peas, shallots
  • Legumes: Beans, chickpeas, lentils, red kidney beans, baked beans, soybeans
  • Wheat: Bread, pasta, most breakfast cereals, tortillas, waffles, pancakes, crackers, biscuits
  • Other grains: Barley and rye
  • Beverages: Beer, fortified wines, soft drinks with high-fructose corn syrup, milk, soy milk, fruit juices

Keep in mind that the purpose of such a diet is not to completely eliminate FODMAPs — which is extremely difficult.

Simply minimizing these types of carbs is considered sufficient to reduce digestive symptoms.

There is a wide variety of healthy and nutritious foods that you can eat on a low-FODMAP diet, including (1, 14):

  • Meats, fish and eggs: These are well tolerated unless they have added high-FODMAP ingredients like wheat or high-fructose corn syrup
  • All fats and oils
  • Most herbs and spices
  • Nuts and seeds: Almonds, cashews, peanuts, macadamia nuts, pine nuts, sesame seeds (but not pistachios, which are high in FODMAPs)
  • Fruits: Bananas, blueberries, cantaloupe, grapefruit, grapes, kiwi, lemons, lime, mandarins, melons (except watermelon), oranges, passionfruit, raspberries, strawberries
  • Sweeteners: Maple syrup, molasses, stevia and most sugar alcohols
  • Dairy products: Lactose-free dairy products, hard cheeses and aged softer varieties like brie and camembert
  • Vegetables: Alfalfa, bell peppers, bok choy, carrots, celery, cucumbers, eggplant, ginger, green beans, kale, lettuce, chives, olives, parsnips, potatoes, radishes, spinach, spring onion (only green), squash, sweet potatoes, tomatoes, turnips, yams, water chestnuts, zucchini
  • Grains: Corn, oats, rice, quinoa, sorghum, tapioca
  • Beverages: Water, coffee, tea, etc.

However, keep in mind that these lists are neither definitive nor exhaustive. Naturally, there are foods not listed here that are either high or low in FODMAPs.

In addition, everyone is different. You may tolerate some foods on the list of foods to avoid — while noticing digestive symptoms from foods low in FODMAPs for other reasons.

Many commonly consumed foods are high in FODMAPs.

It’s generally recommended to completely eliminate all high-FODMAP foods for a few weeks.

This diet is unlikely to work if you only eliminate some high-FODMAP foods but not others.

If FODMAPs are the cause of your problems, then you may experience relief in as little as a few days.

After a few weeks, you can reintroduce some of these foods — one at a time. This allows you to determine which food causes your symptoms.

If you find that a certain type of food strongly upsets your digestion, you may want to permanently avoid it.

It can be difficult to get started and follow a low-FODMAP diet on your own. Therefore, it’s recommended to seek the advice of a doctor or dietitian who is trained in this area.

This may also help prevent unnecessary dietary restrictions, as certain tests can help determine whether you need to avoid the FODMAPs fructose and/or lactose.

Summary It’s recommended to eliminate all high-FODMAP foods for a few weeks, then reintroduce some of them one at a time. It’s best to do this with the help of a qualified health professional.

FODMAPs are short-chain carbs that move through your intestines undigested.

Many foods that contain FODMAPs are considered very healthy, and some FODMAPs function like healthy prebiotic fibers, supporting your friendly gut bacteria.

Therefore, people who can tolerate these types of carbs should not avoid them.

However, for people with a FODMAP intolerance, foods high in these carbs may cause unpleasant digestive issues and should be eliminated or restricted.

If you frequently experience digestive upset that lowers your quality of life, FODMAPs should be on your list of top suspects.

Though a low-FODMAP diet may not eliminate all digestive problems, chances are high that it may lead to significant improvements.