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Irritable Bowel Syndrome (IBS) Health Center

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Finding the Right Diet for IBS

Expert Patsy Catsos, MS, RD, answers questions about eating for IBS.

What's the best diet approach if you suspect you have IBS?

Eating smaller, more frequent meals spread throughout the day instead of larger meals can lead to less discomfort for some people.  What is really important is to identify the foods that are causing the symptoms. 

For individuals with diarrhea, gas, or bloating, or if a high-fiber diet fails, I suggest a two-week trial FODMAPS elimination diet. (FODMAPS stands for fermentable oligo-, di-, and monosaccharides and polyols.)

What is the FODMAPS approach?

You'll work with your physician and registered dietitian to eliminate all foods that contain the five forms of carbohydrates (lactose, fructose, fructans, sugar alcohols, and galactans) for a trial period of 1-2 weeks.  If FODMAPS carbs are causing the symptoms, relief can occur in just a few days.

You follow the elimination period with a challenge of reintroducing one of the FODMAP carbs and observe symptoms. Additional FODMAP carbs are slowly added back, one at a time.  At the end of the reintroduction phase, a final diet emerges with only those FODMAP carbs that are fairly well tolerated.  

The goal is to find the most liberal and varied diet possible that still keeps symptoms under control. Most people find they can still include their favorite foods if they exercise care. For example, a person who discovers that fructans (found in wheat) cause a lot of distress might find they can’t tolerate wheat at every meal, but may be able to tolerate one portion of wheat without a problem.

Is the FODMAPS approach accepted in the medical community?

Health care providers have known for years about the GI impact of select FODMAPS, such as lactose and sugar alcohols. Fructose and galactan intolerance are a bit newer. Although it is very well accepted and widely practiced in Australia, it is a new idea for most health care providers in the U.S.

The FODMAPS approach is unique because it views all of these carbohydrates as one big system, looking at the forest instead of the trees. Some providers are concerned that the FODMAPS is too complicated, but many patients are very motivated and willing to do anything to feel better.

Is a gluten-free diet a good option for IBS sufferers?

Gluten-free diets are very popular right now for a wide variety of conditions. When you eliminate gluten, you also eliminate wheat products that contain fructans, one of the FODMAPS carbohydrates.

Why are some carbohydrates more problematic than others?

Eating certain carbohydrates can cause gas, bloating, and watery diarrhea for some IBS sufferers. Lactose, or milk sugar, is one example many people are familiar with. If your bowel has difficulty tolerating lactose, when you eat it -- especially in high doses or when you eat it alone -- bacteria in the large intestine ferment it, and it can result in gas and painful bloating as well as excess flatulence.

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