FODMAP 101: Detailed Beginner's Guide
As FODMAPs enter the colon, they become a food source for bacteria and cause various gastric distress symptoms.

Irritable bowel syndrome (IBS) affects about 1 out of every 10 people. IBS symptoms include stomach discomfort, bloating, gas, diarrhea, and other digestive disorders when people consume certain foods.

The issue is that you may not know which specific food or component triggers your IBS symptoms. Furthermore, IBS symptoms can appear at any age. As a result, various diets such as gluten-free and paleo diets were introduced aiming to address suspected sources of IBS symptoms.

The low-FODMAP diet has gained popularity in the last decade, and it helps roughly 86 percent of people with IBS

Foods are usually categorized into the following:

  • FODMAP-free
  • Low-FODMAP
  • High-FODMAP

The purpose of a low-FODMAP diet is to minimize or eliminate your consumption of high-FODMAP foods and replace them with FODMAP-free and low-FODMAP alternatives.

What are FODMAPs?

FODMAP is an abbreviation that stands for:

  • Fermentable oligosaccharides (fructans and galactans)
  • Disaccharides (lactose)
  • Monosaccharides (fructose)
  • Polyols (sugar alcohols)

The gut cannot adequately absorb FODMAPs, and whatever is absorbed will be fermented rapidly.

As FODMAPs enter the colon, they become a food source for bacteria and cause various gastric distress symptoms such as:

4 categories of FODMAPs

Four categories of FODMAPs include:

  1. Oligosaccharides: Oligosaccharides are classified into two types that include
    • Fructans: They are found in
      • Onions
      • Garlic
      • Artichokes
      • Wheat products
  2. Galactans: They are found in
    • Lentils
    • Beans
    • Broccoli
    • Brussels sprouts
    • Most of the products that contain soy
  3. Disaccharides: Lactose, the most well-known disaccharide, is found naturally in milk and most other dairy products such as yogurt, soft cheese, and ice cream. Lactase is a naturally occurring digestive enzyme that helps the body to digest lactose. If lactase (which is produced by the cells lining the intestinal wall) is absent, the body cannot digest these sugars.
  4. Monosaccharides: Fructose, which is present in most fruits, is one of the most common monosaccharides. Fruits that contain equal levels of fructose and glucose are more easily digested because fructose is better absorbed when coupled with glucose. Fructose and glucose are two different forms of sugars that have the same molecular formula but different chemical structures.
  5. Polyols: Polyols are also known as sugar alcohols and are found in xylitol or sorbitol sweeteners. Polyols are present in some fruits such as cherries and vegetables such as mushrooms.


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What is a low-FODMAP diet?

A low-FODMAP diet is all about lowering your FODMAP consumption. Unlike most diets, a low-FODMAP diet is not designed to help you lose weight, and it is certainly not for everyone.

People who have gastrointestinal disorders or poor digestion may follow the low-FODMAP diet to reset their gut bacteria and alleviate their symptoms. The low-FODMAP diet simply eliminates high-FODMAP foods and replaces them with low-FODMAP alternatives. It is a question of understanding which foods and substances to avoid, as well as carefully reading every food label.

Because not everyone has the expertise or attention to detail to go on a low-FODMAP diet on their own, they may require the assistance of a nutritionist, dietitian, or gastroenterologist.

Low-FODMAP foods include:

  • All meats
    • Fish
    • Poultry
  • Oils
  • Herbs and spices
  • Seeds and nuts (except pistachios)
  • Fruits 
    • Bananas
    • Blueberries
    • Cantaloupe
    • Grapefruit
    • Grapes
    • Kiwis 
    • Lemons
    • Limes
    • Mandarin oranges
    • Passionfruit 
    • Raspberries
    • Strawberries
  • Lactose-free dairy products and hard cheese
  • Kale
  • Lettuce
  • Chives
  • Olives
  • Parsnips
  • Potatoes
  • Radishes
  • Spinach
  • Squash
  • Sweet potatoes
  • Tomatoes
  • Turnips
  • Yams
  • Water chestnuts
  • Zucchini
  • Grains
    • Corn
    • Oats
    • Rice
    • Quinoa
    • Tapioca

How to follow a low-FODMAP diet

A low-FODMAP diet limits meals containing poorly absorbed carbohydrates, then gradually reintroduces them until particular triggers are discovered. It is crucial to remember that a low-FODMAP diet is a diet plan and not a conventional one. If you do not follow all three steps, you should not do it at all. 

All the three stages should be completed under the supervision of a physician ideally with the assistance of a dietitian who specializes in gastrointestinal issues. Because a low-FODMAP diet is restricted, people who try to follow it on their own may consume less than the recommended daily dosage of some nutrients. 

Three steps of a low-FODMAP diet include:

  1. Elimination: The first stage is the elimination stage which lasts between two and six weeks. The objective is to avoid as many high-FODMAP meals as possible. If your symptoms improve, there's a strong chance that one or more of the items you eliminated is the cause of your discomfort.
  2. Reintroduction: As the name suggests, you are allowed to gradually reintroduce higher-FODMAP items into your diet to see which you can tolerate or not. You must gradually introduce all categories of high-FODMAP foods one at a time. You must even provide three days between each category such that the symptoms caused by the previous category foods will be removed from your system completely. High-FODMAP meals that were previously tolerated are likewise avoided during this washout phase. If you start experiencing any symptoms, you must stop the intake of that FODMAP group and start with a three-day wash period before attempting another FODMAP group.
  3. Personalization: During this phase, you begin to modify your longer-term diet by gradually reintroducing higher-FODMAP items that you can tolerate into your meals and snacks while avoiding just the foods that provoked your symptoms.


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What are the goals of a FODMAP diet?

A FODMAP diet is a three-step diet designed to help control the symptoms of irritable bowel syndrome (IBS). IBS is a common gastrointestinal disorder that causes symptoms such as abdominal discomfort, bloating, flatulence, and changes in bowel habits such as diarrhea, constipation, or both.

The goals of a FODMAP diet are to:

  • Learn which foods and FODMAPs you tolerate and which cause IBS symptoms. Understanding this will enable you to adopt a less restricted, more nutritionally balanced diet in the long run, restricting those items that aggravate your IBS symptoms.
  • Determine whether your IBS symptoms are affected by FODMAPs. A low-FODMAP diet will not help everyone with IBS. Therefore, it is crucial to determine if you are 1 of the 34 percent of IBS sufferers who improve on food or 1 of the 14 percent who do not experience symptom relief on diet and must therefore investigate other IBS therapy.

9 high-FODMAP foods to avoid

Nine high-FODMAP foods to avoid include:

  1. Onions with garlic
  2. All legumes and lentils
  3. Wheat and wheat-based items, as well as rye (in excessive quantities); gluten-free bread or muffins
  4. Artichokes, asparagus, sugar snap peas, and green peas
  5. Watermelon, peaches, apples, cherries, nectarines, pears, mango, avocados, and dried fruits
  6. Meat/protein options include sausage/processed beef (breaded fish or meat)
  7. Almonds, pistachios, and cashews
  8. Ice cream, custard, and plain cow's milk and yogurt
  9. High-fructose corn syrup with honey

Bottom line

If you have irritable bowel syndrome, the low-FODMAP diet may help you relieve symptoms, so see your doctor and a nutritionist who specializes in digestive health about it. Because the diet is so rigid, it may not be your best long-term option if you wish to preserve variation in your diet. However, following the diet with the assistance of a specialist will assist you in identifying the specific items that irritate your stomach.

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Medically Reviewed on 6/23/2022
Image Source: Getty image

FODMAP Diet: What You Need to Know: