Comment by heymijo | Hacker News Reader

Comment by heymijo | Hacker News Reader

>"Riders are able to eat so many carbohydrates on the bike now, almost twice as much as before."

>“But what has changed is the way riders get their glycogen fix. New formulations from nutrition brands like Maurten, Precision Fuel and Hydration, and Science in Sport means the age-old carb “ceiling” of 60-90 grams per hour has been blown into another orbit.” “Consumption thresholds have been shifted thanks to “hydrogel” delivery models and new glucose-fructose ratios that ensure what goes down, stays down.”

I would have liked to see some actual details about the carbohydrate changes that have made the increased tolerance so much larger.

I looked at the three brands mentioned and the actual carbohydrate sources listed were tried and true things like maltodextrin [1], maltodextrin/fructose [2], and glucose/fructose [3].

I thought I might see something like highly branched cyclic dextrin. Since it doesn't seem to be any new form of carbohydrate, I'm curious what ancillary ingredients and/or ratios are proving to be the difference maker(s).

[1] https://www.scienceinsport.com/eu/go-isotonic-energy-gels-si... [2] https://www.precisionhydration.com/us/en/products/pf-30-gel/ [3] https://www.maurten.com/products/gel-160-us

I believe this is just referring to the glucose:fructose ratio now being closer to 1:1 than what it used to be. In the old days people only looked at glucose and the 60g/hr limit is more or less for that metabolic pathway. Fructose takes a different path so you can easily go to 120g if you are using a 1:1 mix. Also the old 60g/hr limit isn’t universal so that is how you get some people that can handle 150g+

Just adding my own info here:

When I rode, years ago, my intake was ~110g/hr during 100mi+ rides. This was with the GU brand gels which is a mixture primarily compose of maltodextrin and fructose.

> I thought I might see something like highly branched cyclic dextrin

I just learned about HBCD but its advantage seems to be that its high molecular weight slows down digestion and absorption in the gut. This allows for a more sustained release of glucose into the bloodstream, providing a steady source of energy during prolonged activity. But in biking you can eat on the go, so you don't really need a slow release source.

The main biking innovation seems to be training and using a 1:1 glucose to fructose ratio to maximize both metabolic pathways. But since HBCD is just a slow-release glucose source it's still competing for the same limited metabolic pathway as glucose consumed directly.

I think the author is also try to describe how cyclists train and how recent findings about recovery allow athletes to be constantly consuming calories. But the article is vague and repetitive and it's hard to know exactly what the author is trying to say.

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