Why Are Tour De France Riders Using Ketones?

In recent years, there has been a lot of hype around the use of a new ‘super fuel’ within the peloton, in the form of exogenous ketone supplements. 

You may have seen riders chugging from a small bottle at post-race interviews or teams sponsored by ketone brands, but what exactly are Ketones, and what are the reported benefits for a rider’s performance?  

You may have heard of the ketogenic diet, a massively restrictive diet in which less than 5% of the diet is derived from carbohydrates, with a very large proportion of the diet from sources of fat and a little protein (to prevent excess protein being converted into glucose and bringing the individual out of ketosis). By consuming this diet for as little as a couple of days, the body is shifted into a state of ketosis, whereby in the absence of carbohydrates, the body will become better at using fat as a fuel source and essentially, the liver will begin to produce ketones as an alternative fuel source for important organs, particularly the brain.

From a pure cycling performance perspective, there are a number of issues with the ketogenic diet. By removing carbohydrates, you are also effectively removing the top gears that allow you, as a cyclist, to perform high-intensity exercise. Given most races are won or lost on the ability to produce these types of efforts, ketogenic diets are really only ever going to aid/not be negative for performance in those who are racing at a slow enough speed and long enough for fats to be able to cover all of the energy needs.  Arguably multiday ultra-endurance events like the the race across America may be the only types of events whereby this dietary approach may be of benefit.

Back in the early 2000, a group of researchers at Oxford University secured a significant research grant from the military to complete some research into exogenous ketone supplements, and since then, the interest in these compounds has sored. They set about manufacturing ketones that could be consumed and put the body into a state of ketosis without the need for the dietary restriction to induce a state of ketosis. In effect, proving the benefits of ketones, without having the negatives of having a low carbohydrate intake typically required to induce ketosis.

So what do ketones actually do and what are the potential benefits to taking them?

The effects of ketones on the body are quite wide ranging, not only do they act as as alternative fuel source to the typical fuels of carbohydrate and fat, but can have a whole host of other impacts.

 A key focus of any nutrition strategy is typically enhancing performance. However, the research into ketone supplements to date hasn’t shown a clear positive impact on performance. The evidence as a whole shows that ketones don’t improve performance. Many studies actually show a negative impact owing to the negative impact some ketone supplements can have on the gut and the increase in acidity that it induces within the body. Ketones may provide an additional fuel source and may, therefore, potentially spare or impair the use of glycogen.

 So why are teams still using them? Aside from the obvious commercial aspect (i.e. teams being paid to use these products for marketing benefit), there are impacts of ketone supplements beyond pure performance.

 In particular, ketones have been shown to help reduce the symptoms of overtraining when riders undertake heavy blocks of training/racing (i.e. stage races like the tour de France). They may help increase muscle protein synthesis and help prevent the catabolic state that comes from heavy bouts of training. They may positively impact cognitive performance and finally increase EPO (the protein responsible for stimulating red blood cell production) within the body.

 There are still lots of questions to answer with ketones and we don’t have a really clear picture yet as to exactly the dose that is required to maximise benefit, or exactly what these benefits are and under what conditions they occur. In elite sport where budgets are pretty significant, they may know something that we don’t from there own research and testing, or may simply be leaving no stone unturned.

When you consider the cost of a ketone supplement, with a single dose costing in the region of £40-60, you’ll need to have a pretty significant budget and have every other more affordable and effective strategy (i.e. fuelling and hydration) absolutely dialed in before considering this.

Coach Ben