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Athlete digestive ails: Could certain carbs be triggering your gastric troubles?

I remember back to my pre-dietitian, heavy triathlon training days and one of the most memorable things that pops into my mind is…bloating. Aaaahhh, yes…the pain from trying to crank out a track workout while the innards are churning and burning. If only I knew then what we’ve learned now.

Digestive problems such as gas, bloating, diarrhea, and/or constipation certainly aren’t new to the woes of endurance athletes. Some athletes may have a diagnosable disease such as Celiac or Crohns, but quite commonly the issue is Irritable Bowel Syndrome (IBS), especially considering 10-15% of the population experiences it. IBS is characterized by a combination of gastrointestinal symptoms with an unknown cause and a physician will often diagnose it after ruling out all other possibilities.

The good news is while we don’t know 100% why IBS occurs, we do have a better idea these days of which foods may be exacerbating the issue. The bad news is they are commonly found in foods and supplements used by athletes, in addition to lots of foods that are quite healthy.

This recent approach to helping someone with IBS is called a low FODMAP diet. FODMAP stands for Fermentable Oligo-, Mono-, and Disaccharides and Polyols and refers to types of carbohydrates which are poorly absorbed in the small intestine. As a result, they travel into the large intestine and contribute to gas production, diarrhea, and constipation. It is important to note that these carbohydrates are not the cause of IBS but rather contribute to symptoms. For some reason individuals with IBS are more sensitive to gut expansion and discomfort, along with often have delayed or hypermotility (in other words, foods pass through slower or quicker than normal).

FODMAPs are found in a wide variety of foods – some are high in FODMAPs, some are low. An individual working with a dietitian may be asked to follow a low FODMAP diet for anywhere from 2 to 6 weeks in order to determine if symptoms improve. Once this elimination period is over, foods higher in FODMAP are added back in one by one to determine which are tolerated. Some folks may simply be experiencing a “load” issue – they can tolerate small amounts of high FODMAP foods but multiple servings in a day may cause symptoms by evening time.

While a low FODMAP diet may bring relief, it’s important to understand it limits the variety in a diet and shouldn’t be followed long-term. Identifying foods that are tolerated (and in what amounts) is the ultimate goal. Sadly, most sports foods (gels, chews, some drinks) are high in FODMAPs and coming up with a fueling plan can be challenging.

First, let’s take a look at the types of FODMAP nutrients.

Below is an example listing of foods high in FODMAPs. This list is by no means all-inclusive, but it gives you an idea of its expansiveness and the planning required to meet energy needs while avoiding irritants.

Because of the wide variety of foods which are limited on a low FODMAP diet, it’s best to tackle this issue with a dietitian, in particular for athletes with high energy needs during endurance training and races. Additionally, if you are experiencing unexplained GI symptoms such as cramping, diarrhea, bloating, and/or constipation you should have a discussion with your physician prior to attempting this plan. Although it could bring relief, it may not be IBS and it is important to rule out other conditions. Also, since the low FODMAP approach requires removing wheat, someone who is suspected of having Celiac disease should get tested prior to removing wheat from the diet.

Although IBS remains a mystery somewhat, the low FODMAP approach can certainly provide relief for an endurance athlete and a balanced diet if followed appropriately.

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