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Old 09-06-19, 04:41 PM
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Drew Eckhardt 
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Originally Posted by Tulok
Thank you! So you’re saying 1/4-1/3rd of gross Calories used during a ride? If it was 3000 Calories in 5 hours, I’d want to consume at least 150-200/hour?
Originally Posted by Tulok
Thank you! So you’re saying 1/4-1/3rd of gross Calories used during a ride?
Yes.

If it was 3000 Calories in 5 hours, I’d want to consume at least 150-200/hour?
No. It's better to eat less if you're not already at your ideal cycling weight and save room for better testing good if you are.

As a rule of thumb trained cyclists can do at least four hours on stored carbs at 4 kcal/gram.

You have 25g of blood sugar and 100g of liver glycogen for 500 kcal total getting you 1500 - 2000 kcal of range.

On top of that you have 400g / 1600 kcal of glycogen in your muscles which would be 4800 - 6400 kcal of range, but can't move it between muscles or even fast and slow twitch fibers with the former seeing limited recruitment at an endurance pace. Maybe 1/4 of that is usable?

On five hour rides I eat a 200-250 kcal energy bar after four hours of wall clock time which might be 2000 kj/kcal in good shape totaling 2500 kcal.

On 6000 Calories in 10 hours, you'd eat 150-200 an hour.

This assumes a reasonable estimate of calories off measured power output, where 1 kj = 1 kcal is the rule of thumb most people use.

More intense rides shift the energy substrate utilization to carbs, although that limits duration.

Last edited by Drew Eckhardt; 09-06-19 at 06:48 PM.
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