Slowing output for sports

Hello! I’m about to kick off the football season (soccer) and I’m wondering about slowing output before games? If during the match o have to go I’ll need subbed off and won’t be aloud back on again, so I’m wondering if there’s any specific foods/medical items or some such that have helped others?

Might well just be a case of eating and praying which is totally fair, but just incase there’s someone out there with any tips!