Following the 2022 Tour of Flanders, a photo circulated on social media showing a detailed nutrition plan carefully taped to the handlebars of race winner Mathieu van der Poels. Some rough math indicates that the Dutchman consumed more than 100 grams of carbohydrates per hour while winning the 169-mile race in just over six hours, a remarkable digestive feat, considering that traditional sports nutrition guidelines say Our ability to absorb carbohydrates tops out at about 90 grams per hour.
To outsiders, Van der Poel’s mega-carb intake seemed like a distinct novelty. But in the year and a half since then, very high carbohydrate doses have become an emerging trend among elite endurance athletes. New science shows that it is actually possible to consume up to 120 grams of carbohydrates per hour, and some professionals reportedly even exceed that. The unanswered question for now is whether it makes you faster.
The latest study to address this issue was recently published Journal of Applied Physiology By a research group led by Robert Jacobs of the University of Colorado Colorado Springs. Jacobs and his colleagues use real-world data to simulate a range of physiological characteristics seen in typical marathon runners and calculate how many carbohydrates they would need to successfully run a sub-two-hour marathon. .
If you’re fit, lean, and properly carb-loaded, you already have an adequate supply of carbohydrates when you start a marathon, primarily in the form of glycogen in your liver and muscles. Is stored in. The exact amount depends on several factors, including the size of your liver and legs, but on average researchers estimate that elite male marathoners start with 690 grams of glycogen and female marathoners start with 499 grams.
At first glance, this seems promising, as they calculated that a two-hour marathon should require 612 grams of carbohydrate for elite men and (because men are smaller on average) 528 grams for women. The problem is that you can’t empty the tank completely for several reasons. One is that running doesn’t use every muscle in your legs equally, so when you hit the wall the less used muscle fibers will still have some glycogen stored. Overall, you may use about 62 percent of your stored carbohydrates during a two-hour marathon, leaving a large deficit that you’ll need to make up by drinking or eating more carbohydrates.
To make the numbers work for a two-hour marathon, Jacobs and his colleagues calculated that an average elite male marathon runner would need to consume 93 grams of carbohydrates per hour, while an average female would need 108 grams per hour. Which is much more than 90. Gram maximum in current sports nutrition guidelines.
This is an interesting analysis, although it is worth acknowledging that it puts the cart (what marriage) Like Running) in front of the horse (who was actually capable). We could run a similar calculation on how many carbs we would need to run back-to-back marathons in four hours, and that calculation would yield an astronomically high number, but the number would have no meaning in the real world. The limit of endurance depends on more than carbohydrate supply.
Still, Jacobs offers three arguments why the two-hour marathon number is worth taking seriously. One is that recent laboratory studies have shown that humans are, in fact, capable of burning more than 90 grams of exogenous (from drinks or food rather than internal storage) carbohydrates per hour. For example, a study published last year by Tim Podloger, an exercise physiologist at the University of Birmingham and nutritionist for the Bora-Hansgrohe Pro Cycling Team, fed cyclists 120 grams of carbohydrates per hour and found that they were able to burn more carbohydrates than 90 Were. Of those grams per hour. (The rest will either be excreted or stored for later use.) Reaching this level of carb burning involves drinking a mixture of glucose and fructose at a ratio of 1:0.8, which in many current sports is 1:0.8. There is a change from the normal ratio of :0.5. Drinks and gels.
The second argument is that the digestive system can adapt. Of course, if you try to feed a group of volunteers 120 grams of carbohydrates per hour, their stomachs will rebel and you will conclude that it is impossible to absorb that much. But try training your abs for a few months, as the Matthew Van der Pols of the world have done, and who knows what you’re capable of?
The third argument is anecdotal: many fast athletes in sports such as cycling, triathlon and running reportedly exceed 90 grams of weight per hour. VeloJim Cotton wrote a fascinating article in October about the carbohydrate revolution in cycling. Aitor Viribe Morales, a nutritionist at Ineos Grenadiers, told Cotton that energy intake has changed drastically over the past five or six years. This is one of the biggest reasons why cyclists have been producing such high power for so long, and how they are able to reproduce it day to day.
Again, let’s agree that moving the goalpost to 90 to 120 grams per minute is laudable. But there are reasons to be cautious before jumping on the bandwagon. For one thing, elite endurance athletes can burn carbohydrates more quickly and for much longer periods of time than the rest of us. One reason that earlier studies concluded that humans could not burn more than 90 grams per hour is probably that the subjects were well trained rather than simply elite.
Even if you can absorb 120 grams per hour, it won’t make you faster. In study of podloggers, cyclists suffered more burns Exogenous When they consumed 120 carbohydrates per hour instead of 90 grams, but this did not reduce their rates Endogenous Carb-burning, that is, they were still depleting glycogen stores in their muscles just as fast. Other studies have seen the same effect, and some studies have even found that consuming high levels of carbohydrates actually suppresses fat burning so effectively that you deplete your internal carbohydrate stores more than you otherwise would. Burn faster, which is quite the opposite. What would you expect.
As it happens, Medicine and science in sports and exercise Recently there has been an academic debate published, they call it the Contrasting Perspective, about whether ketogenic diets are beneficial for athletic performance. Arguing the pro-keto case is Tim Knox; Arguing against this are Lewis Burke and Jamie Whitfield of Australian Catholic University, who led a series of studies on ketogenic diets in elite racewalkers. I’ve written about some of Burke and Whitfield’s results here, and I’m not going to repeat that entire discussion. My general view is the same as it was then: Keto for endurance is a good idea in theory, but it doesn’t live up to the hype when you actually test performance.
Interestingly, ketogenic diets are beneficial for athletic performance Despite the headline, Nokes’ pro-keto case doesn’t take much time to argue that ketogenic diets enhance performance. Instead, he focuses on a slightly different argument: Contrary to conventional wisdom, consuming more carbs during exercise doesn’t make you faster. In short, they argue that the only benefit of eating carbohydrates during exercise is that it keeps your blood sugar high enough to provide energy to your brain, which would otherwise leave you feeling overly tired. This explains why performance benefits from sports drinks have been seen in many studies, even though Podlager and others have found that super-high carb doses do not actually maintain internal carb stores for long. To keep blood sugar up, tip figuresOnly 20 grams of carbohydrates per hour will be needed, regardless of whether you normally eat a low-fat or high-fat diet.
So should we increase our carb intake to 120 and above, or dial it back to 20? The honest answer at this point is that both ideas are hypothetical. The world of elite endurance sports is voting with its feet (or, perhaps, its stomach) in favor of carb-mania. I guess they’re right, assuming your primary interest is winning races at the Olympic Games. But we must keep in mind that no one has proven that 120 grams per hour makes you faster than 90, and even the case for 90 to 60 is not indisputable. The only way to settle the argument is with more data from well-designed experiments or by winning races like Mathieu van der Poel.
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