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Eating 90 to 120g of carbohydrates per hour is the new trend in endurance sports, and especially in cycling, to achieve performance. But between gains of a few watts for the pros and the little-known health effects, this overconsumption raises questions. Can you really ride faster by consuming more sugar without compromising your metabolism in the long term?
By Guillaume Judas – Photos: depositphotos.com
Lately, A new nutritional injunction has emerged in the world of endurance sports : consume 90 to 120g of carbohydrates per hour during exercise to optimize performance. This approach comes in parallel with the increase in performance of high-level athletes, whether in cycling or running. Every year, records are broken, surpassing those set during the heyday of doping.
These results are bound to raise questions, especially since this trend is even observed in major cyclosportives and ultra-endurance events. It gives pride of place to energy product brands that promise excellent results in the form of gels and other hyper-concentrated supplements with their optimized formulation and undeniable practicality, but sold at €120 per kg.
More This recommendation to consume so much sugar during exercise, often presented as revolutionary, raises questionsIs it suitable for everyone? What are its long-term health impacts? Shouldn't amateur cyclists adopt a consistent and healthy eating strategy?
A succession of nutritional dogmas over the years
Nutritional recommendations in endurance sports have often oscillated between extremes. In the 1980s, a diet with 70% slow carbohydrates (pasta, rice, semolina, etc.) was popular. In large mass events (cyclosportives, marathons and triathlons), the famous pasta party The previous evening's diet was very widespread. This method consisted of consuming large quantities of starchy foods the night before a long-distance race in the hope of starting the next day with the maximum amount of glycogen (super fuel for exercise) stored in the liver and muscles.
Le Scandinavian dissociated diet was also fashionable for big goals, alternating deprivation in the first days of the week and carbohydrate overload in the run-up to the race.
In the 2010s, another trend emerged, with carbohydrate deprivation, similar to the ketogenic diet. The goal of this type of diet is to stimulate fat burning (lipolysis) to preserve glycogen and increase endurance levels. During certain training phases, athletes would undertake long runs consuming only protein and fat (a bit like the deprivation period of the Scandinavian dissociated diet), reserving carbohydrate intake only for the race.
Fortunately, These dietary dogmas often end up being called into question in the face of physiological realities and the long-term effects on physical... and mental health..
A questionable strategy
Since the early 2020s, another trend has become more prevalent: the consumption of large amounts of carbohydrates just before, during, and just after exercise. Seeing professional cyclists plowing recklessly into large bags of candy while boarding the bus just after the finish of a Tour de France stage is surprising, coming shortly after the reign of Chris Froome and his salmon-avocado diet.
We can see it in this YouTube video by Remco Evenepoel, who tells us about his meal before a time trial, where he consumes... half a liter of Fanta (at about 16 minutes)!
Recent studies (mostly observational), often relayed by the energy product industry, validate the consumption of 90 to 120 g of carbohydrates per hour. For example, Podlogar et al. (2021, Sports Medicine) show that these high intakes can improve performance during prolonged efforts by maintaining glycogen reserves, but only in trained athletes who have accustomed their digestive system.
More These benefits are measured over short periods of time, without assessing the long-term consequences on metabolic or cardiovascular health. There are currently no studies on the long-term effects of this type of carbohydrate overload. Although the risks are mitigated by the context of sugar consumption during exercise, we do not know the state of health of athletes who run on superfoods in a few years.
The risks of overconsumption of carbohydrates
Consuming 90 to 120 g of carbohydrates per hour is almost like ingesting the equivalent of a liter of soda every 60 minutes (Stéphane Cascua, docdusport.com). During the last Tour de France, Kevin Vauquelin, 7th in the general classification, even revealed in the show Bike Club having trained to absorb up to 150g per hour. An extreme case not necessarily representative. But In elite athletes, such intakes can cause high blood sugar levels (1,8 to 2 g/L), close to diabetic thresholds (Stéphane Cascua, docdusport.com).
Repeated consumption of simple sugars (gels, energy drinks) can overload the digestive system, increasing the long-term risk of chronic disorders, such as insomnia syndrometestin irritable or a sensitivity to fructose. According to Podlogar et al. (2021, Sports Medicine), absorbing so many carbohydrates requires prior digestive training, often inaccessible to amateurs, which increases these risks. In addition, an unbalanced diet, poor in antioxidants (vitamins, minerals), can induce oxidative stress and mild inflammation.
A 2020 study (Journal of Applied Physiology) also suggests that chronic high carbohydrate intake may reduce fat oxidation, creating an addiction to sugars, although varied training, such as fasted sessions, can limit this effect.
Products rich in simple sugars also expose teeth to an acidic environment, promoting enamel erosion and cavities. A 2019 study (Scandinavian Journal of Medicine & Science in Sports) shows an increased risk in endurance athletes, especially in cases of poor post-exercise oral hygiene.
Excessive consumption of simple carbohydrates could, in theory, disrupt insulin sensitivity in the long term, particularly if the non-exercise diet is also high in sugars or if energy expenditure is insufficientHowever, endurance athletes, who metabolize these carbohydrates during exercise, are less vulnerable than the general population.
Match carbohydrates to distance and intensity
For amateur runners, whose metabolism consumes fewer calories, an overload of carbohydrates can cause immediate digestive problems (hence the need for a gradual increase in carbohydrate consumption and specific training as Kevin Vauquelin pointed out), and above all saturate the blood with glucose, thus increasing the risk of storage as fatGaining weight is not really the goal of amateurs who invest in health sports.
Physical activity, on the contrary, should be a powerful tool for preventing diabetes and cardiovascular diseases.By depleting muscle glycogen stores, training improves insulin sensitivity, facilitating glucose uptake at rest. This reduces the risk of type 2 diabetes, but only if you limit yourself to a reasonable intake of carbohydrates during and after exercise.
At low intensity, the body learns to burn fat, releasing fatty acids and increasing "good" cholesterol (HDL). This adaptation protects the arteries and optimizes the use of lipid reserves. A dietary strategy that promotes lipolysis, through training on an empty stomach or with a low carbohydrate intake, is therefore more sustainable and beneficial for health than massive sugar intake..
For a demanding cyclosportive, an intake of 40 to 60 g of carbohydrates per hour is sufficient to stabilize blood sugar and prevent major failure due to glycogen depletion. For a cycling race on route, we can go up to 80 g, or even 90 g, especially on short and intense events, such as criterium.
At a lower intensity but over longer efforts such as ultra or long-distance gravel events, the body consumes moretage fats. Carbohydrates must be supplemented with digestible lipids and proteins (dried fruits, salted oilseeds, cheese, ham, biscuits, potagis). This varied diet limits digestive disorders, responsible for example for 50% of dropouts in ultra according to a study by theInternational Journal of Sports Medicine (2019).
A balanced approach to performing and staying healthy
The recommendation of 90 to 120 g of carbohydrates per hour, although supported by some studies, is unsuitable for the majority of athletes and potentially harmful in the long term, even if there is a lack of certainty on this subject. A reasoned strategy, based on a regular but not excessive intake of carbohydrates and a varied diet, optimizes performance while preserving health.Before you try to do like the pros, consider gradually increasing your training volume and intensity and adapt your nutritional strategy to the level of the events you are participating in.
