Sugars and refined carbs (think doughnut, cookie, maple bar, white bread, potatoes, pretty much all candy) are pretty useless for
muscle-
building, as well as leading to intense sugar cravings. Junk food is also good at building up fat in your body and clogging your arteries, too. All that is bad for your skin, as well.
A lot of exercises, you can do in the privacy of your room, or in a cool place like a garage if you get too warm doing them.