The low FODMAP diet

In this blog we’re going to break down what a low FODMAP diet actually is, who it is for, and how it works. 

There are so many different diets or eating patterns that someone can choose from that vary the way we fuel our bodies with many different reasons people try different diets.

The low FODMAP diet is intended as a short-term diet that is used strategically to support people dealing with unpleasant gastrointestinal symptoms. Because of it requiring restriction of a range of different foods, it is important to use this diet only as intended short term to learn and understand individual food triggers for symptoms.  

The low FODMAP diet is primarily intended to be used by people with irritable bowel syndrome (IBS) but it may be effective for people dealing with other gut symptoms. 

What is a low FODMAP diet? 

The low FODMAP diet is an elimination diet where for at least 4-6 weeks all foods containing medium or high quantities of FODMAPs are removed from your diet. This length of time allows the gut to settle with the intention to eliminate symptoms.  

After the elimination phase FODMAPs are reintroduced one at a time to see which FODMAP containing foods are the ones causing symptoms. This is a great systematic way to pin point food triggers for each individual to understand the cause of gut symptoms.  

What are FODMAPs? 

FODMAPs are a group of short-chain carbohydrates/sugars that we can’t fully digest, instead, bacteria in our large intestine use them as fuel. The term FODMAP stands for fermentable oligosaccharides, disaccharides, monosaccharides and polyols.  
 
These carbohydrates travel to the small intestine where they attract water, eventually reaching the large intestine, where they are fermented by bacteria which produce gas. When these bacteria produce excess gas, along with having excess water in the intestines, the intestinal wall stretches and expands. This is what can cause bloating and discomfort. People with IBS have a highly sensitive gut and this stretching can cause feelings of pain and discomfort and lead to other unpleasant symptoms like constipation and diarrhoea. 

FODMAP types and examples of high FODMAP foods 

Fructans: In a wide range of foods including fruit, vegetables and grains. Some of these include, grapefruit, persimmon, dates, onion, garlic, leek, wheat and rye containing foods like bread and pasta. 

Galacto-oligosaccharides (GOS): In many pulses/legumes and some nuts. Some of these include green peas, black beans, red kidney beans and navy beans, split peas, cashews and pistachios. 

Sorbitol: Primarily in fruit and sugar free lollies. Including apple, pear, avocado, most stonefruit, fresh coconut, coconut milk and sugar free lollies containing sorbitol. 

Mannitol: High in some vegetables including mushrooms, cauliflower, celery, sweet potato and snow peas. 

Fructose in excess of glucose: When there is more fructose than glucose in a food the fructose is harder to absorb because glucose helps with the absorption of fructose. Some examples of these include apple, pear, grapes, asparagus, honey and fruit juice. 

Lactose: Cow’s milk products including milk, yoghurt, custard and some soft cheeses. 

Who is it for?  

The low FODMAP diet is generally recommended for people struggling with IBS symptoms and may be beneficial for people working to manage other gut symptoms.

Common symptoms for gut related conditions like IBS include excessive gas, bloating, stomach pain, cramping, constipation and diarrhoea.  

There is a range of dietary patterns and other elimination diets that may be more suitable for people working to address different symptoms. Other elimination diets can be more restrictive and are generally focussed on a wider range of foods that are more commonly seen as triggers. The low FODMAP diet is more concerned with the foods that cause gut issues because of the gut bacteria fermenting FODMAPs and causing gut symptoms.  

Why it can be detrimental to do a low FODMAP diet for an extended period of time. 

Because a low FODMAP diet involves significant restriction of a wide range of different foods, there is potential for it to result in inadequate nutritional intake of essential vitamins, minerals and fibre.  

FODMAP foods act as prebiotics which are beneficial for the gut, providing food for our good gut microbes. These microbes can then produce short chain fatty acids and other beneficial compounds which can have significant beneficial health effects for our gut health, reducing inflammation, supporting brain health and overall wellbeing. Ideally we want to have a range of fibre rich and FODMAP containing foods in our diet to support our gut and overall health. 

Throughout the reintroduction phase of the diet there may be certain foods causing reactivity, this doesn’t mean it will never be able to be tolerated as symptoms can vary over time. When gut health is supported and trigger foods are reduced, it is possible that sensitivities to trigger foods may diminish over time. 

The goal of a low FODMAP diet is to understand trigger foods and reactivity so that each individual's diet can be expended and include as much range as possible over time while still managing gut symptoms to improve quality of life. 

 Why it can be incredibly beneficial to work with a qualified nutritionist or dietician while undergoing a low FODMAP diet.  

This can help by ensuring a strategic and personalised approach to low FODMAP restrictions and reintroduction’s. It is helpful to rule out possibilities of symptoms like coeliac disease and working together in the reintroduction phase can be very helpful. Once reintroduction’s have been tested a nutritionist/dietician can provide a personalised plan and support based on results from trigger foods. 

Support and guidance can be helpful when working through health challenges and dietary restrictions and it can be great to get support when there is any confusion, frustration or struggles. 

Because the low FODMAP diet requires eliminating significant amounts of food it is important to ensure adequate nutritional intake during the diet which a professional can help support. 

Overall, a low FODMAP diet can be very beneficial for people struggling with IBS and it can significantly improve quality of life, helping each individual understand their food triggers.  Using the low FODMAP diet as a short-term strategic approach to understanding specific triggers can be a great way to improve quality of life, day to day wellbeing, and provide more understanding of what foods are causing symptoms.