Carbohydrate for runners
Modern sports nutrition theory has us locked down hard when it comes to the subject of carbohydrate for runners. The rules, we are told, are that we we need loads of carbohydrates for running performance.
This isn't even close to true, and nor is it helpful for performance, stomach happiness or longterm health. Teaching the body to burn fat better is the cheapest performance enhancer anyone serious about endurance can choose, and while carbohydrates are still important as a macronutrient, they need to be of the highest quality possible (whole foods are the best sources) and volume and timing needs careful management.
Despite this, there is a whole industry dedicated to just making runners eat more and more carbohydrates in a blind and fruitless search for performance. Having told us how we must eat a ton of them, the same industry then supplies a never-ending array of gels, bars, drinks, powders and goo. Conveniently, being highly-processed synthetic carbohydrates, these products can be made in massive bulk for peanuts, before being dressed up with a little pseudo-science and some natty packaging to be sold for a massive markup.
Carbohydrate for runners: timing is everything
This 1984 report from the British Journal of Sports Medicine makes very interesting reading, because while it agrees a carb-based meal three hours before a marathon can indeed help, it very clearly states that carbs after that or during the race are all-but useless and can even impair performance.
Quite how we got from this point of sensibility to the insane sugar-heavy 'nutritional strategies' hurled at us from all angles today (see this example from the London Marathon guide) beggars belief.
For particularly dedicated readers, the full BJSM text can be found here. But just in case wading through the entire ten-page scientific report isn't to your liking, we've summarised some key points.
Carbohydrate for runners: taking carbohydrates near, or during, a race, in any form, is a bad thing
"The ingestion of dilute glucose solutions (5%)… does not appear to improve endurance performance (Felig et al, 1982). Paradoxically, glucose ingested before prolonged sub-maximum exercise appears to contribute to, rather than delay, the early onset of fatigue."
Carbohydrate for runners: incorrect carbohydrate use buggers up your ability to burn fat, making you less efficient and tired more quickly
"...when a concentrated glucose solution was ingested within an hour of the start of prolonged exercise the result was an increase in the carbohydrate metabolism... and a reduction in endurance performance. The mechanism appears to involve an increase in plasma [blood] insulin concentration, following an ingestion of the glucose solution, which in turn exerts an antilipolytic* effect. The decrease in circulating fatty acid concentration following the increase in plasma insulin denies the working muscles its supply of this fuel and so the muscles use their limited glycogen stores at a more rapid rate.
[*inhibits the breaking down of fat to be used as energy]
Carbohydrate for runners: the more carbs runners eat, the more they need
" …during the run after the high carbohydrate diet, the subject appeared to use more carbohydrate than on the run following the mixed diet."
Stuffing carbohydrate in on the hoof won't really help your performance, but it will make you less able to use your fat stores and more dependent on more and more carbs. Good for the companies selling them, rather less good for you.
Set your body up for fat-burning efficiency and reduce carbohydrate intake for max endurance running performance
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