I think it would be cool if you used less calories while you are sleeping, maybe it is already this way, but it seems like if you sleep 9 hours you use up a lot of calories and sleeping doesn't use too many calories.

I don't think this needs any more tweaking. In real life we humans only save around 63 calories a hour when sleeping in comparison to being awake. Sleeping does save energy but it's not very much.

It's still something and I think is a very valid point, why not take it that 1 small step further? It seems like a simple thing to implement and it is a realistic survival game where every little bit counts.

Jumping too! It's just simple math, more calories upon the button press, Z axis exists already.