The point is that adding some protein after half an hour of exercise will promote muscle growth.
Secondly, the key to becoming a muscular man lies in the principle of exercise: less weight (suitable for eating by yourself), generally no more than 5 groups.
If there is no targeted exercise, you will definitely not get fat. Don't worry about that. However, half an hour's exercise seems a little short. You should do muscle training for half an hour, anaerobic exercise and aerobic exercise for half an hour.
How long do you want to be a muscle man? You must have targeted muscle exercise, and the most important thing is your exercise intensity.