Gluten-Free Diets for Cyclists: Myths, Realities, and Performance Impact

Going gluten-free has become quite trendy over the last decade or so. There are some who have serious allergies to gluten and need to, at the very least, reduce the amount of gluten in their diets or, in more extreme cases, eliminate it completely, but there are many who declare overall health benefits despite their gut not having any issues. As cyclists we are always bombarded with different diet and nutrition ideas that are supposed to benefit not only our health but also our ability to ride our bikes further and faster. Would reducing the amount of gluten in our diet really make a difference to our cycling?

Firstly, what exactly is gluten? It is a group of proteins found in the cereal grains wheat, rye and barley and this means, all foods containing these grains also contain gluten, including bread, pasta, breakfast cereal, crackers, flour, cakes and biscuits. That is a lot of stuff that cyclists eat!

Although it’s developed a bad reputation, gluten actually plays an important role in food production. It is the stretchy protein that allows dough to rise, giving bread its springy, elastic texture. For a small percentage of people, gluten has to be avoided. Around 1% of the World’s population have coeliac disease. A condition where gluten triggers an overactive immune response, causing damage to the lining of the small intestine, which affects the way food is absorbed. This leads to symptoms like weight loss, bloating, diarrhoea, anaemia and tiredness. 

The number of pro cyclists turning to gluten-free diets has jumped in recent years, thanks to the idea that ditching gluten can give performance a boost. So what is it that drives the decision? According to results from surveys and team interviews, it comes from the perception that gluten triggers inflammation in the gut, leading to symptoms that affect training. Although there is no strong evidence for this in people without coeliac disease, it’s an attractive selling point for cyclists, because around seventy percent of endurance athletes who compete at recreational level do report digestive symptoms.

There are other explanations for these symptoms though. For one, the large amount of carbohydrates that are needed to fuel long cycling sessions can cause bloating and diarrhoea, as some groups of sugars are poorly absorbed by the small intestine. Secondly, intense exercise itself can also trigger inflammation in the gut, because blood flow is directed away from the digestive system to the muscles. This could potentially trigger digestive symptoms.

So could a gluten-free diet help? In a recent attempt to determine just that, scientists at the University of Colorado studied the effects of a short-term gluten-free diet in a group of non-coeliac competitive cyclists, who had no history of irritable bowel symptoms. The results showed no difference between the two diets on any marker of performance, digestive health or inflammation. Although longer-term studies are needed, this does cast a shadow on gluten-free diets having any kind of performance enhancing advantages. 

So, even if there are no real performance enhancing benefits from cutting gluten from our diets, are there any other advantages to giving up on it? Unfortunately these are also not conclusive. Claims of weight loss with a gluten-free diet are common, but this is usually just a side-effect of cutting out calorie dense foods like cake and biscuits and just the general inconvenience of having to bake a potato in comparison to making a sandwich.

There’s also no evidence that a gluten-free diet is healthier. In fact, it can often lead to an overreliance on processed food and studies show long-term gluten-free diets tend to be low in fibre, B vitamins, iron and zinc, which are all linked with energy production and performance.

The most significant positive side-effect of following a gluten-free diet is often just the simple fact that cyclists are made more aware of exactly what they are eating. Many of us end up eating vast quantities of the same things, day in and day out. Trying to reduce the amount of gluten in our diet has the effect of us varying our food choices more, and probably eating more fruit and veg than we might have before, and that is not necessarily a bad thing.