Navigating the Low FODMAP diet


Written by Lizzie Gralton – Accredited Dietitian

Are you someone who suffers from bloating, abdominal pain, constipation, or altered bowel habits? Has your GP recommended the low FODMAP diet following a recent Irritable Bowel Syndrome (IBS) diagnosis?

If this is you, then the low FODMAP diet may be the key to healing your gut. 

Firstly, what is FODMAP?

“FODMAP” is an acronym that stands for a certain food group of fermentable short-chain carbohydrates:

  • Fermentable – compounds that are broken down (“fermented”) by the bacteria in the large intestine.
  • Oligosaccharides – a type of carbohydrate/sugar that consists of two or more monosaccharides (single-chain sugars).
  • Disaccharides – molecules composed of two sugar units.
  • Monosaccharides – Single sugar molecule. 
  • And Polyols – naturally occurring and man-made sugar alcohols. 

When we eat food containing FODMAPs, the large intestine can digest these incorrectly due to underlying gut issues and intolerances to certain sugars, resulting in fermentation. Although fermentation can lead to growth of healthy bacteria in the gut, it has a side product of carbon dioxide, hydrogen and methane gas. This may result in flatulence, bloating, and abdominal pain and distention. 

List of FODMAP-containing foods:

  • Fructose – found in most fruits such as apples, pears, and watermelon, as well as some vegetables like onions and artichokes.
  • Lactose – found in dairy foods like milk, yoghurt, and some cheeses. 
  • Fructans – found in many vegetables such as garlic, onions, broccoli, and grains like wheat and rye.
  • Galactans: Found in legumes and beans like lentils, chickpeas, and kidney beans.
  • Polyols – sugar alcohols which are commonly found in sugar-free products like chewing gum, mints, and certain fruits such as stone fruits like peaches, plums, and avocados.

High FODMAP Foods and common triggers for people with gut sensitivities:

  • Vegetables: artichoke, garlic, onion, asparagus, cauliflower, leek, mushrooms, sugar snap peas.
  • Fruits: mango, apples, blackberries, cherries, figs, grapefruit, nectarine, peach, pear, plum, and watermelon. 
  • Grains & cereals: wheat, kamut, rye, barley, spelt, wheat noodles.
  • Dairy: cream cheese, sour cream, custard, ice cream, cow’s milk, and yoghurt.
  • Legumes, nut, and seeds: cashews, pistachios, baked beans, black beans, broad beans, chickpeas, fava beans, split peas.
  • Added ingredients & sweeteners: inulin, high fructose corn syrup, agave, honey. 
IBS Diet

Phases on Low FODMAP Diet:

This diet is not meant to be long-term. Instead, it’s a way to ease your gut symptoms and enable us to investigate what foods trigger you and how much. It is essential to complete this diet under the guidance of a FODMAP trained Dietitian to ensure no nutrient or energy deficiencies, or worsening of gut symptoms occur. 

Phase 1: Elimination Phase

This is a highly restrictive diet that is not a long-term solution. This diet should be followed with dietitian guidance for 2-6 weeks depending on how your body responds. 

Phase 2: Reintroduction Phase

After you have relief from your gut symptoms, this phase allows you to challenge certain FODMAPs at separate times. It is important to isolate each challenge by having a FODMAP-free “washout” period (3 days) in between each FODMAP challenge. This will ensure we can identify the true cause of your symptoms. 

Phase 3: Tailored Meal Plan 

During this phase, you collaborate with your Dietitian to develop a personalised diet plan that identifies trigger foods and portions causing gut symptoms. This enables you to devise strategies to mitigate or anticipate future digestive discomfort. It’s important to note that gut tolerance may change over time due to various factors like changes in gut microbiome, medications, mental health, and stress.

Who should you speak to?

If this is you, then it is recommended to seek support from an Accredited Dietitian who has specific training in the low FODMAP diet to guide you correctly. Our Dietitians Lizzie & Ellen are here to help you solve your gut symptoms.  

Why is it important to seek professional support and not just use Dr Google?

  1. Professional support allows an accurate evaluation as to whether a low FODMAP diet is necessary or whether there is a less restrictive approach you could try first. 
  2. A restrictive diet like low FODMAP carries the risk of micronutrient and energy deficiencies, which can have long-term health impacts. Professional guidance ensures nutritional adequacy.
  3. If done incorrectly, the diet may worsen gut microbiome (dysbiosis) and lead to the worsening of gut symptoms. 
  4. Dietitians will give you practical strategies and food swaps to make your experience more manageable and enjoyable. 
  5. A dietitian can develop an individualised and tailored meal plan that considers your specific dietary preferences and lifestyle. This will ensure all food groups are incorporated and reduce the amount of foods restricted from your diet. 

To book an appointment with Lizzie or Ellen, reach out to our friendly team.

Written by Lizzie Gralton


The Specialist Network is a dedicated group of private surgeons providing an extensive range of specialist services to the local community. Our surgeons stay updated on the latest surgical advancements and routinely consult in the fields of colorectal and general surgery.

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