What do you eat/drink before you hunt?
My thing to eat before an evening hunt is simply a butter sandwich - it seems to stick with me and helps ward off cold as temps fall. Also, I bring an apple with me and eat it in the stand. I don't drink anything in the hour or two before heading out, unless it is morning when I will have 1 cup of coffee right when I get up just to ward off a caffeine headache.
Seems to work for me well as I can sit 3+ hours without needing to "go" or "fumigate" the woods.