> burning a hundred calories

GP left out the units but is clearly talking about grams ("absorb ... 100 carbs per hour"), not calories (no one needs training to absorb 25g/hr). Carbs are 4 kcal/g. 100g of carb (400 kcal) an hour isn't replacement level for even casual athletic efforts, but it does mitigate the loss of glycogen in muscle somewhat.

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/

Where does discussion on gut training occur? All I know is you need a 5:4 ratio of glucose to fructose? Then when you train, you use the gels and the more you do it, the more capable your gut gets at absorbing without distress.

Is that all the science to it?

Wow so he was absorbing 400 calories per hour with this gel, but he was likely burning 3-4x that amount (or even more) while running 13.1 miles per hour!

Because calories simply do not matter. At high intensities of working out, it's the amount of carbohydrates you can consume that allow more fuel to be burnt.

"In the aerobic exercise domain up to ~100% of maximal oxygen uptake (VO2max), CHO is the dominant fuel, as CHO-based oxidative metabolism can be activated quickly, provide all of the fuel at high aerobic power outputs (> 85-90% VO2max) and is a more efficient fuel (kcal/L O2 used) when compared to fat."

https://www.gssiweb.org/sports-science-exchange/article/regu...

It’s also confusing that most nutritional labels say “calories” (Cal) when they really mean kilocalories (kcal). And those are different from regular (‘small’) calories (a measure of energy needed to heat 1g water 1c).

1 food calorie as listed on a food label is enough to heat 1kg of water by 1c

It's deliberate, because you generally do not want calories from fat or protein during a marathon or other running race.

it is a lot more challenging when running than when biking. The jostling is not your friend.

Yeah, I just literally use table sugar, which is 1:1 glucose:fructose. Maurten et al using 1:0.8, close enough! And I don't believe the hydrogel thing is any magic, just marketing.

But yeah, this is a thing. There is some gut distress for sure at higher levels of intake. See guy finishing second -- still under 2 hrs! immediately puking, which is fairly common at the high intakes. I've heard of Blumenfeld (the triathlete) taking like 200g/hr or more. Insane. Though he's had some epic GI disasters too, lol.

Not burning, eating. They are eating 100g of carb per hour. Burning 1000+ calories.

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