The low FODMAP diet

New to the low FODMAP diet? Then have a look at this short overview explaining what the low FODMAP diet is and where to begin!

What is the low FODMAP diet?
The low FODMAP diet is an elimination and reintroduction diet used in managing Irritable Bowel Syndrome (IBS) symptoms.

What does FODMAP stand for?


In simpler terms FODMAPs are fermentable short chains of carbohydrates. This means that when ingested these carbohydrates are poorly absorbed in the small intestine and they are fermented by bacteria in the gut leading to a build up of gas, bloating and pain. Malabsorption of these FODMAPs can also lead to water entering the bowel leading to diarrhoea. Studies have shown that reducing the intake of these fermentable carbohydrates improves symptoms in 70% of IBS sufferers.

A closer look at FODMAPs… Where are they found?

There two major types of fermentable oligosaccharides:

  • fructo-oligosaccharides (FOS) also known as fructans found in wheat, rye, onions and garlic
  • galacto-oligosaccharides (GOS) found in legumes and pulses

The fermentable disaccharide is lactose which is found in milk, soft cheeses and yoghurts.

The fermentable monosaccharide is fructose which is found in honey, apples, certain fruit and high fructose corn syrup.

The main fermentable polyols are sorbitol and mannitol which are found in fruit and vegetables and are used as artificial sweeteners therefore are common in diet and sugar free products. Other polyols to stay away from are xylitol, maltitol, isomalt, and polydextrose.

The low FODMAP diet

The low FODMAP diet works by limiting the intake of the FODMAPs for 6 to 8 weeks. If symptoms improve during the elimination weeks the groups can be reintroduced back in. Not all IBS sufferers have the same triggers. Some may find that they can tolerate some of the FODMAP groups with no adverse symptoms. Reintroduction is usually done to identify personal triggers and reintroduce as many foods back into the diet as possible. Reintroduction can also help identify the amounts of certain FODMAPs that can be tolerated.

Where should you start?

Starting the low FODMAP diet can be overwhelming. It requires you to drastically change your diet and likely eliminate some of your favourite foods. Read the tips below on how to make this experience easier. Despite being difficult at first the diet results in great improvements in symptoms for most making the sacrifice worth it.

  1. If you are interested in starting the low FODMAP diet speak with your GP and seek a dietetic referral. This is important to ensure you have a balanced diet once eliminating the high FODMAP foods.
  2. Check out the Monash university website and download their phone app. The Monash University are the only reliable source as they test the foods to determine FODMAP content. The money for the app goes towards the testing of more foods. They also have a blog now. Check it out here.
  3. Familiarise yourself with high FODMAP and low FODMAP foods and the portion sizes before starting the diet.
  4. Look at your current diet and identify any high FODMAP sources. Think about ways you can substitute these. Preparation is key to be able to stick to the diet and not feel like you’re missing out or find you’re feeling hungry.
  5. Start reading food labels. For help in identifying high FODMAP ingredients on food labels see this blog post.
  6. Check out the list of low FODMAP products in the UK here to make your shopping experience easier.
  7. Find out tips on eating out on a low FODMAP diet here.
  8. Make sure you are also aware of other common IBS triggers such as caffeine, alcohol, and insoluble fibre. Read the article on IBS and first line dietary advice here.

Any questions? Feel free to post questions in the comment box below.


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