The Low FODMAP Diet is designed to help sufferers of IBS reduce and manage their symptoms. It was designed to be implemented in 3-phases, with the end goal of balancing the least restrictive possible diet with the greatest sustainable improvement in symptoms.
Phase 1 is the low FODMAP phase where Fructose, Oligosaccharides, Disaccharides, Monosaccharides and Polyols are restricted from the diet to relieve symptoms and create a baseline to operate from. Suitable alternative foods should be found to replace those being restricted. It usually lasts for 2-6 weeks.
Phase 2 is a phase where the FODMAPs are individually tested to establish tolerance levels to specific foods. This process can take a significant amount of time as there are a lot of variations in the types of FODMAPs, serving sizes, and foods that need to be trialled. It usually lasts for 6-8 weeks.
Phase 3 is the longer-term application of the information gathered in phase 2. A more personalised FODMAP diet is established which incorporates as many well-tolerated foods as possible, while only restricting and replacing poorly tolerated ones. FODMAP tolerance can change over time, so foods that weren’t initially tolerated can be tried periodically.
For a more detailed breakdown of the FODMAP diet, you can check out our full post on The Low FODMAP Diet.
The Types of FODMAPs in fruit.
Of the 5 FODMAPs, fructose and sorbitol are the main types present in fruit, and these need to be tested during phase 2 of the FODMAP diet.
Above is a summary of which fruits are high in FODMAPs. These are not suitable for phase 1 of the diet and are most likely to cause symptoms in those who are sensitive to them.
After phase 1 of the diet is complete, the higher FODMAP foods can be trialled to identify which ones, and how much of each can be safely added back into the diet.
What Fruits are low FODMAP?
When following a low FODMAP diet, a priority regardless of the phase of the diet is to replace foods that are being restricted with alternatives of similar nutritional value. This is important to help maintain good health, and ensure nutrient deficiencies do not develop. It is also to help maintain the diversity of the gut microbiome.
The image above features a summary of the fruits which are low in FODMAPs in normal serving sizes.
When in the restrictive phase 1 of the diet, it is important to remember fruit is an excellent source of nutrients including vitamin C, folate, potassium and antioxidants. It does not have to be cut out altogether.
There is typically a dose-response relationship with food and symptoms (more on this further down) – but as seen above there are many examples of low FODMAPs fruit which are typically suitable to use as substitutions for higher FODMAP fruit.
Which Fruit Are Good For Phase 2 Challenges?
In phase 2 food challenges, when testing individual tolerance to FODMAP-containing fruit, it is important to remember some types of fruit contain multiple types of FODMAPs – i.e. both fructose and sorbitol. Multi-FODMAP fruits include watermelon, cherry, clingstone peaches, nashi pears, and certain types of dried fruit (apple/apricot/pear/prunes).
Such fruit would not be suitable for testing the response to just sorbitol or just fructose in phase 2.
For example, if someone wanted to test tolerance to sorbitol a nashi pear would not be suitable to do so as the excess fructose (not the sorbitol) may cause symptoms. This can incorrectly give the impression that sorbitol was the cause, resulting in the unnecessary restriction of sorbitol containing foods.
A yellow peach would be a good food to test sorbitol tolerance, as it is high in sorbitol, but not in fructose or any other FODMAPs. Mango would be a good choice for testing fructose tolerance as it is high in fructose but not in other FODMAPs.
As mentioned earlier, there is a strong dose-response relationship between the amount of a FODMAP that needs to be eaten to trigger symptoms.
Taking the example of mango:
- 40 grams (roughly 1/5 of a cup of cubed mango) is considered low FODMAP
- 45 grams (roughly 1/4 cup) is considered to have a moderate amount of fructose
- 140 grams (half of a mango) is considered to be high in fructose
During the challenge phase you may find that you have no symptoms when eating 45g or 70g of mango, but eating half a mango gives you symptoms. This might indicate you have a moderate tolerance to fructose-containing foods. Having established this level of tolerance, you would then move on to testing a different FODMAP/food.
This may sound complicated, and the FODMAP protocol can be difficult. This is why guidance from a qualified dietitian is always recommended when undertaking the FODMAP diet.
A list of dietitians who are well qualified to help guide you through the process can be found in this list of Monash University approved FODMAP dietitians. The Monash Low FODMAP Diet app is also a great smartphone tool for helping navigate the ins and outs of the diet.
Remember the overall goal of implementing a FODMAP diet is including the widest variety of foods possible for that individual. Every individual will have different tolerances that will be discovered throughout the FODMAP challenge.
Tyler has a Bachelor of Nutrition and Exercise Sciences and completed his Masters of Dietetics through the University of Queensland after moving away from a long career in the fitness industry. As part of his education he worked with dietitians at the Brisbane Broncos rugby league club, is currently working with the Qld Women’s Rugby 7’s team, and has continued to follow his passion for performance nutrition.
Tyler is a believer in ‘practice what you preach’. Outside of helping people achieve their goals through diet and exercise, he competes in powerlifting and loves experimenting with his own nutrition and diet to find the best ways to support various training and body composition goals.