Generally speaking, we all recommend supplementing protein after 30-60 minutes of fitness, not necessarily drinking protein powder.
This is because, at this time, the human body absorbs protein better, and protein is the main raw material for synthesizing muscle, which helps to increase muscle.
But breaking down muscles is not so easy. When energy consumption is insufficient, muscles will be consumed.
Generally, sugar is consumed first, then fat is consumed, and finally muscle is turned.
Consume sugar in about 20 minutes, and exercise within 90 minutes consumes fat. It is only after 90 minutes or more and a lot of exercise that it is possible to break down muscles.
Professional fitness, welcome to ask.