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A comment on Sawe becomes first athlete to run a sub-two-hour marathon in a competitive race. Parent comment

Re:Sawe becomes first athlete to run a sub-two-hour marathon... by wging on Sunday April 26, 2026 @08:55PM (#47916547)
I've read that even if you absorb it all, there's some question about whether it's useful. This Alex Hutchinson article suggests, among other things, that it may spare your fat stores rather than your muscle glycogen:

> Even if you can absorb 120 grams per hour, it might not make you faster. In Podlogar’s study, cyclists burned more exogenous carbs when they consumed 120 rather than 90 grams per hour, but that didn’t reduce their rate of endogenous carb-burning—that is, they were still depleting the glycogen stores in their muscles just as quickly.

https://www.outsideonline.com/health/training-performance/en...

https://archive.ph/Vpk0h

https://pmc.ncbi.nlm.nih.gov/articles/PMC9560939/

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Re:Sawe becomes first athlete to run a sub-two-hour marathon... by loeg on Monday April 27, 2026 @12:17AM (#47917644)
That may still be worthwhile if fat is harder to recruit than exogenous carbs.
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Re:Sawe becomes first athlete to run a sub-two-hour marathon... by wging on Monday April 27, 2026 @04:11PM (#47926692)
What does 'harder to recruit' mean though?
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Re:Sawe becomes first athlete to run a sub-two-hour marathon... by Earw0rm on Monday April 27, 2026 @11:30AM (#47922943)
Kejelcha is 6'1" and under 130lb.

What fat stores?

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Re:Sawe becomes first athlete to run a sub-two-hour marathon... by loeg on Monday April 27, 2026 @12:37PM (#47923860)
It doesn't take much. If an elite burns 1500-2000 kcal running a marathon, even ignoring glycogen and exogenous carb, that's only ~195-260g of body fat (~7.7 kcal/g). Even at an extremely lean 4% body fat, Kejelcha would have 2360g of body fat available. (He's probably in the slightly higher 5-10% range.)

(And obviously, the majority of those 1500-2000 kcal are coming from stored glycogen rather than fat.)

If we're only talking about the marginal difference between 90 and 120 g/hr of exogenous carb, then that's 60g over two hours or 240 kcal -- equating to 31g of stored body fat. That's nothing.

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