What are FODMAPs?

The term FODMAPs stands for fermentable oligosaccarides, disaccharides, monosaccarides and polyols. These carbohydrates are grouped according to their chain length and are found in a wide range of foods and food products from pasta sauce to watermelon.

A Low FODMAP Diet

The low FODMAP diet was researched and developed by leading researchers at Monash University Department of Gastroenterology to treat symptoms of irritable bowel syndrome, with 70% success rate. Here is where it gets exciting for athletes who struggle with gastrointestinal issues.

  1. Gastrointestinal symptoms reported in irritable bowel syndrome are analogous to symptoms of exercise-induced gastrointestinal syndrome.

  2. The actions of FODMAPs in the gut may worsen gastrointestinal symptoms caused by the many factors related exercise?

Low FODMAP Diet for Athletes

The History and Road to Low FODMAP Diets in Athletes

Leading into the London 2012 Games I worked with a number of Canadian athletes heading to the Olympics who had all of a sudden switched to a gluten-free diet. The uptake of this diet was suddenly exploding among athletes. At this point in time, there was a lack of evidence substantiating the beneficial or negative effects of a gluten-free diet outside of the clinical realm. In high level sport nutrition there was no athlete-specific data except a plethora of confusing anecdotal online articles. It’s easy to dismiss this trend as a bandwagon effect. However, once in a while athletes do things, nutrition or otherwise, ahead of the research curve. I was curious if this was the case with gluten-free.  

We know that athletes’ guts undergo unique stress when undertaking strenuous exercise (e.g. cycling at 75% Wmax for 45 minutes). Under conditions of exercise stress a combination of reduced blood flow to the gut (splanchnic hypoperfusion) and altered enteric nervous system activity leads to a series of changes in the body that may result in gastrointestinal symptoms, and/or acute or chronic health complications. Given that many foods can trigger or worsen gastrointestinal symptoms perhaps gluten, a known dietary trigger, played a role in symptoms reported to occur in 30-90% of athletes. 

Researching the Effects of a Gluten Free Diet on Athletes

I was fortunate enough to take the reins of my PhD research and put together a piece of this puzzle. We found out that 41% of athletes followed a gluten-free diet at least half the time (link to paper). Athletes also reported a long list of believed benefits of going gluten-free, but we had no actual data to confirm this. The ‘belief effect’ can go a long way but when working with the world’s best athletes my advice better be based on evidence. In running the first gluten-free diet study in athletes, our research concluded that a gluten-free diet did not have any beneficial or negative effects in endurance athletes that didn’t clinical require gluten-avoidance. However, a surprising link was found between gluten-free diets, a family of short-chain carbohydrates known as FODMAPs, and their role in exercise-associated gastrointestinal symptoms in athletes.  

Instantly pieces of this gastrointestinal puzzle as it related to athletes started coming together and we conducted a series of landmark studies with some really exciting and practical findings. It has taken me a few years to follow my dream of sharing these findings on a less boring and less of an academic platform, so here goes.

Research and the Results of a Low FODMAP Diet

Remember, I mentioned above that athletes are known to do things before research tests it out? Initially, our survey-based study quantified that 55% of athletes eliminated at least one high FODMAP food to reduce gastrointestinal symptoms. About 85% reported symptom improvement. This tells us that many athletes may already be self-selecting the cut-out foods high in FODMAPs, but not actually realize the reason. For example, milk or cow’s milk based dairy products are one of the most highly avoided foods by athletes. Lactose is in the FODMAP family. Similarly, can you even count how many times have you heard an athlete say “gluten or breads/pasta makes them feel bloated.” Wheat-based products are high in fructans, again a member of the FODMAP family. Likely, it’s the automatic decrease in specific FODMAPs that improves gastrointestinal symptom when athletes switch to avoiding gluten-containing (wheat based) foods. Break though! FODMAPs and not gluten may be the reason that so many athletes feel better when they go gluten-free. Could this special diet be a successful tool to reduce the severity and frequency of exercise-associated gastrointestinal symptoms?

Now, before we all start cutting out one hundred foods let’s be methodical and systematic. All sports scientists share my pet peeve: Non-evidence-based nutrition recommendations. When we started looking in the role of FODMAPs in exercise- associated gastrointestinal systems data was non-existent and initially limited to our work which limited to one survey study and a case study. What to do next to delve into this exciting new concept!

A Study of Endurance Athletes using a Low FODMAP Diet

To test this out we conducted the first well-controlled double-blind cross-over study comparing high FODMAP to low FODMAP diet in runners with exercise-induced gastrointestinal syndrome. In short, runners were fed either a low or high FODMAP diet for 6 days and then switched over the other diet. The diets were similar to their normal eating habits and completely blinded (impossible to tell apart). The runners followed their normal training with two prescribed hard running sessions during each intervention period. Food intake and training was simulated during each intervention. We also monitored psychological wellbeing because stress can also influence gastrointestinal symptoms. Drum roll please….we found for the first time that the low FODMAP diet reduced gastrointestinal symptoms in these runners.

Since, this landmark study a few other researchers have continued to study the use of FODMAP reduction to reduce gastrointestinal symptoms in athletes. Some achieving the same high standard of academic research execution and some missing some key factors leaving the research findings unreliable. So, a word of advice, be skeptical about some of the research that is published. Some studies are poorly conducted and should not have gotten through the peer review process.

Don’t jump before you learn

My PhD research gave me the opportunity to discover something novel that may truly help athletes achieve top performance and improve quality of life. Coincidingly, market reports predict the low FODMAP diet to become the next gluten-free diet. Sounds like I should be excited right? As an evidence-based high-performance sport dietitian this is actually concerning. A boom in a diets’ popularity paves a path for the misuse of the low FODMAP diet and poor online information to surpass evidence-based advice. Monash University researchers have dedicated enormous amounts of time to educate medical professionals and the general population about the appropriate use of the low FODMAP diet. To build on this I am using my unique position as the first to research FODMAPs in athletes to connect athletes with evidence-based information on the role of low FODMAPs for sport.

My Intentions of this Resource

  1. To provide foundational tools to help athletes determine if FODMAP reduction is an appropriate tool for them.

  2. To provide a platform for athletes learn about the pros and cons of a low FODMAP diet.

  3. To access individualized leading-edge sport nutrition strategies.

  4. To keep a pulse on and share progressive research on the use of FODMAP reduction to reduce symptoms of exercise-induced gastrointestinal syndrome.

Symptoms and Diseases that can be Improved by a Low FODMAP Diet

Symptoms that can be Improved by a Low FODMAP Diet

  • Gas

  • Pain

  • Bloating

  • Abdominal distention

  • Abdominal pain

  • Diarrhea

Diseases that can be Improved by a Low FODMAP Diet

  • Irritable Bowel Syndrome or IBS

  • Small Intestinal Bacterial Overgrowth (SIBO)

  • Other Functional GI Disorders

A List of Low FODMAP Foods

Low FODMAP Vegetables

  • Alfalfa sprouts

  • Bamboo shoots

  • Bean sprouts

  • Bell peppers

  • Bok choy

  • Carrots

  • Chives

  • Cucumber

  • Eggplant

  • Ginger

  • Green beans

  • Lettuce

  • Olives

  • Parsnips

  • Potatoes

  • Tomato

  • Turnips

  • Zucchini

Low FODMAP Protein

  • Beef

  • Pork

  • Chicken

  • Fish

  • Eggs

  • Soy products such as tofu

Low FODMAP Milks

  • Almond milk

  • Coconut milk

  • Rice milk

Low FODMAP Drinks

  • Coffee

  • Fruit juice (not from concentrate)

  • Tea

Low FODMAP Fruits

  • Bananas

  • Blueberries

  • Cantaloupes

  • Grapes

  • Grapefruits

  • Honeydew melons

  • Kiwi

  • Lemon

  • Lime

  • Oranges

  • Strawberries

Low FODMAP Nuts and Seeds

  • Almonds

  • Macadamia

  • Peanuts

  • Pine nuts

  • Pumpkin seeds

  • Walnuts

Low FODMAP Dairy

Lactose-free dairy such as:

  • Brie

  • Camembert

  • Feta Cheese

Low FODMAP Grains

  • Corn flour

  • Gluten-free bread and pasta

  • Oats

  • Oat bran

  • Quinoa

  • Rice

  • Rice bran

  • Sourdough spelt bread

A List of High FODMAP Foods

High FODMAP Vegetables

  • Artichokes

  • Asparagus

  • Beetroot

  • Broccoli

  • Brussels sprouts

  • Cabbage

  • Cauliflower

  • Celery

  • Garlic

  • Mushrooms

  • Onions

  • Snow peas

  • Sweet corn

High FODMAP Dairy

  • Cottage cheese

  • Custard

  • Ice cream

  • Milk

  • Soft cheeses

  • Yogurt

High FODMAP Drinks

  • Alcohol

  • Coconut water

  • Sports drinks

High FODMAP Fruits

  • Apples

  • Apricots

  • Blackberries

  • Cherries

  • Mangoes

  • Nectarines

  • Peaches

  • Plums

  • Prunes

  • Watermelon

High FODMAP Nuts

  • Cashews

  • Pistachios

High FODMAP Grains

  • Breads

  • Cereals

  • Crackers

  • Pastas

High FODMAP Sweeteners

  • Agave nectar

  • High fructose corn syrup

  • Honey

FODMAP resources

Comprehensive Nutrition Assessment Questionnaire by Monash University 

A validated food frequency questionnaire that quantifies the habitual intake of FODMAPs. 

Validated gastrointestinal questionnaire for athletes 

Authored by Ricardo Da Costa and Steph Gaskell this is the first questionnaire to be validated as reliable tool to measure gastrointestinal symptoms in athletes. 

Monash FODMAP app

A must have for any athlete or practitioner. Using a traffic light system app identifies high, moderate and low FODMAP foods but also allows for individualized diet, symptoms and mood tracking.

Download the app