just played the worst badminton in my life. 3 days ago i felt like Lee Yong Dae, today i felt like a i had a case of overnight arthritis, and i couldn't figure out why until i asked my partner if there's any food that causes inflammation. YUP. the night before i had vietnamese ice coffee, and the last couple days, have been drinking pop. let this be a lesson.
that'd be my diagnostic as well. badminton is hard on the body, esp when playing at the level of LYD! even seasoned runners after a tough race need to rest for a few days.
I don't think it is the white sugar per se. As Kwun said, the body needs time to recover. It is well known athletes have to build up physicially and mentally to play at optimum level. Even then, there are variations in their condition from day to day, week to week. When I was doing much more hard core exercise, before going to bed, I would take some protein powder supplements (muscle repair occurs during the night), and take more carbohydrates to replace muscle glycogen. It helped quite a bit.