Coldzera, Niko, Flamie used to be insane players, when they were overweight. They lost weight, but their cs-go performance don't improve.
Actually it is really strange, because low body fat improve ( I mean about 12 - 15%, under 10 % is also unhealthy) improve the brain functions and the reactions.
They also should have better endocrine system, but the performance is still bad.
That's why in Cs Go overweight >>> healthy body
One day has 24 hours. What so you, mean? We don't need to do 20 hours cardio, every single day. Did you ever heard about the Law on Thermodynamics? It's easy to lose weight, but hard to build solid muscle mass.