FODMAP testing is best done using the scientifically based FODMAP Diagnostic Elimination diet.
Breath tests for lactose and fructose have been popular in the past but recent research shows these tests to be inconsistent and unreliable (except for lactose)
malabsorption of fructose is a normal occurrence
fructose breath lasts are unreliable: fructose may be malabsorbed but no symptoms
Lactose breath tests are more clinically reliable.
FACT: The low FODMAP diet is a TEST DIET and not a diet for life. It is used to test if you are reacting to FODMAPs and which FODMAPs you are reacting to.
The FODMAP foods that you are not reacting to are put back into your diet. No need too restrict them.
The FODMAP foods you are reacting to are introduced back in carefully to see how much you can tolerate safely without symptoms.
You end up with a diet that has a lower amount of some FODMAPs and is only restricted where it needs to be to keep you as symptom free as possible.
FACT: Many FODMAPs provide important food for our gut loving microbes. Foods that promote healthy bacteria in our gut are called prebiotics. FODMAPs are prebiotics.
For this reason, cutting out FODMAPs when you don't need is not in your gut's bests interests. Find out more about FODMAPs for our gut health.
The Diagnostic Elimination Diet is based on the information provided by Monash University who are seen as the leaders in the field of IBS and diet therapy.
The Monash University FODMAPs App is an excellent resource that is available on iphones and android providing information on a wide range of foods tested for their FODMAP content.
DIAGNOSTIC ELIMINATION DIET - 3 steps
This is a LOW FODMAP diet not a NO FODMAP diet.
High FODMAP foods are swapped for low FODMAP foods.
Weetbix is swapped for GF weetbix
Wheat bread is swapped for Lofo bread
Milk is swapped for lactose free milk
Apricots are swapped for strawberries
Garlic is swapped for garlic infused oil
The idea is to see if you get symptom relief when all the significant FODMAPs are removed from your diet.
To allow the FODMAPs to wash out of your system and help your symptoms to settle, the elimination phase is usually undertaken for 3-4 weeks. Most FODMAP sensitive people will find relief within 3-4 weeks, although this can vary with relief from symptoms within days or a maximum of 6-8 weeks for the body to adjust.
How long the elimination diet is followed can depend on your relief from symptoms achieved. If after 2 weeks, there is excellent reduction in symptoms then the challenge program can be started.
To ease you into the elimination diet you are supported with:
List useful resources and information explaining how the diet can be implemented
Easy reference diode to fruit and vegetables low in FODMAPs, or low in FODMAPs at reduced serving sizes
Breakfast, lunch, dinner, snack, dessert and drink guides with recipes
Low FODMAP supermarket list
Lots of specific information as required
Support/guidance via e-mail between visits
2. Food Challenges
Chances are that you are not sensitive to ALL the FODMAP foods- just SOME. The challenge program is set up to detect which of the FODMAP foods you are reacting to.
The challenges are simple and each takes a week: 2-3 days of simple challenges and the rest of the week a resting period free from testing. The wheat and onion challenges may take an extra week each.
There are 8 -10 different challenges and the order of the challenges depends on your preferences (see below).
At the end of the challenges- you will have a reaction profile and now can identify the high FODMAP foods causing you grief.
FODMAP Challenge List
Challenges are commenced in any preferred order but fructose and lactose are often first as they are the most basic challenges.
Challenges typically take a week with different set outs depending on your individual sensitivities.
Excess Fructose (honey/mango)
Lactose (milk/ice cream)
Wheat oligosaccharides (bread/ pasta)
Onion & garlic oligosaccharides
Fruit oligoacccharides (grapefruit/raisins)
Beans oligosaccharides (legumes/chickpeas/almonds)
Mannitol (cauliflower/mushroom): 1 food challenged
Combination: for example fuctose & sorbitol (apple/pear)
By re-introucing the trigger foods back into your diet very carefully- it will become clear how much you can safely manage without causing any symptoms.
This is important as foods high in FODMAPs are actually very good for your gut so you should be having as much as you can safely manage for your long term health.
Yao, C. K., and Tuck, C. J. (2017) The clinical value of breath hydrogen testing. Journal of Gastroenterology and Hepatology, 32: 20–22. doi: 10.1111/jgh.13689.
Gibson, P. R. (2017) The evidence base for efficacy of the low FODMAP diet in irritable bowel syndrome: is it ready for prime time as a first-line therapy?. Journal of Gastroenterology and Hepatology, 32: 32–35. doi: 10.1111/jgh.13693.
Barrett, J. S. (2017) How to institute the low-FODMAP diet. Journal of Gastroenterology and Hepatology, 32: 8–10. doi:
Tuck, C., and Barrett, J. (2017) Re-challenging FODMAPs: the low FODMAP diet phase two. Journal of Gastroenterology and Hepatology, 32: 11–15. doi: 10.1111/jgh.13687.