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FODMAP stands for fermentable oligosaccharides, disaccharides, monosaccharides and polyols. It’s a type of carbohydrate that can resist digestion. Some people with digestive issues can benefit by reducing these in their diet.

What you eat can have a major effect on your body, and digestive concerns 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.

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What are FODMAPs?

FODMAP stands for fermentable oligo-, di-, monosaccharides and polyols (1).

These short-chain carbs 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 has a sensitivity to FODMAPs, it 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

What happens when you eat them?

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 conditions 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. This 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 (3).

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

Benefits of a low FODMAP diet

The low FODMAP diet has mostly been studied in people with IBS. This common digestive disorder includes symptoms like:

• gas
• bloating
• stomach cramps
• diarrhea
• constipation

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 (4, 5).

In many cases, they experience major reductions in symptoms and impressive improvements in quality of life (6).

A low FODMAP diet may also be beneficial for other functional gastrointestinal disorders (FGID), a term that encompasses various digestive concerns (7).

If you have an intolerance, then the benefits of a low FODMAP diet may include (1):

• 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 (12).

Foods high in FODMAPs

Here is a list of some common foods and ingredients that are high in FODMAPs (8):

• Fruits: apples, applesauce, apricots, blackberries, blueberries, boysenberries, cherries, dates, figs, grapes, nectarines, peaches, pears, plums, raspberries, watermelon
• Sweeteners: agave nectar, fructose, high fructose corn syrup, honey, isomalt, malt extract, maltitol, mannitol, molasses, sorbitol, xylitol
• Vegetables: artichokes, asparagus, beetroot, broccoli, Brussels sprouts, butternut squash, cabbage, cauliflower, fennel, garlic, karela, leeks, mushrooms, okra, onions, peas, shallots
• Dairy products: ice cream, most yogurts, soft and fresh cheeses (cottage cheese, ricotta, etc.), sour cream, whey protein supplements
• Legumes: beans, baked beans, black-eyed peas, broad beans, chickpeas, fava beans, lentils, pinto beans, red kidney beans, soybeans, split peas
• Wheat: biscuits, bread, most breakfast cereals, crackers, pancakes, pasta, tortillas, waffles
• Other grains: amaranth, barley, rye
• Beverages: coconut water, fortified wines, fruit juices, kombucha, oat milk, rum, soft drinks with high fructose corn syrup, soy milk, tea (chai, chamomile, fennel)

Foods you can eat on a low FODMAP diet

Keep in mind that the purpose of this 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 (8):

Meats, fish and eggs

These are well tolerated unless they have added high FODMAP ingredients, like wheat or high fructose corn syrup.

Nuts and seeds

Nuts and seeds that you can eat include peanuts, macadamia nuts, pine nuts, and sesame seeds but not pistachios, almonds, or cashews, which are high in FODMAPs.

Fruits

• Unripe bananas
• Cantaloupe
• Grapefruit
• Kiwi
• Lemons
• Lime
• Mandarins
• Melons (except watermelon)
• Oranges
• Passionfruit
• Strawberries

Vegetables

• Alfalfa
• Bell peppers
• Bok choy
• Carrots
• Celery
• Chives
• Cucumbers
• Eggplant
• Ginger
• Green beans
• Kale
• Lettuce
• Olive
• Parsnips
• Potatoes
• Radishes
• Spinach
• Spring onions (only green)
• Squash
• Sweet potatoes
• Tomatoes
• Turnips
• Water chestnuts
• Yams
• Zucchini

Grains

• Corn
• Oats
• Quinoa
• Rice
• Sorghum
• Tapioca

Other foods or ingredients

• All fats and oils
• Most herbs and spices
• Sweeteners (maple syrup and stevia)
• Dairy products if they are lactose-free as well as hard cheeses and aged softer varieties (like Brie and Camembert)
• Beverages (water, coffee, green, black, or white 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.

It is not surprising, then, that how much of a food you eat will affect how likely you are to experience symptoms if you have IBS. The individual tolerance to FODMAPs varies.

How to do a low FODMAP diet

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, you may experience relief in as little as a few days.

After three 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 (8).

It can be difficult to get started and follow a low FODMAP diet on your own. It’s highly recommended to seek the advice of a doctor or dietitian who is trained in this area, if you have access to one.

This may also help prevent unnecessary dietary restrictions, since certain tests can help determine whether you need to avoid the FODMAPs fructose or lactose, rather than needing to remove them from your diet.

The bottom line

FODMAPs are fermentable carbs that move through your intestines undigested.

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

So, 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 for 4-8 weeks.

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.