@Odoritomaki 4000 cal as bodybuilding diet just shows that it's a comparatively lazy sport. XD
Elite cross-country skiiers need 8000 calories per day, and there seems to be a general consensus among them that eating is the dull part (and what stops them from getting more training done.
(I found an English source saying much the same, but with slighly lower numbers. Our Swedish star usually ran by 8500 calories, and he definitely said "I'd train more if I could, but I just can't eat more" https://www.nytimes.com/2018/02/23/sports/olympics/cross-country-skiing-food.html )
Those bigger numbers you cited.. well, they seem weird (or fattening).
@Hootanic Oh, in the future you will think about it more than once. Especially when the author wants to add Misora lewd scenes with someone other than Akira.
This manga can only be to things: Ridiculously stupid, flamboyant and over the top or outright realistically depressing. There's no in-between. Most of the time.