You also don't have to completely deny yourself. Go to the subway stands and get a large meat anc cheese samwich with mayo, then just take the bread off, roll up the meat and enjoy. If they have hotdog and hamburger booths, get a dog or a patty minus the bun. As you progress through OWL you will notive you probably have a much higher carb tolerence if your playing competative tennis (I wasn't clear on if you were ap layer or just a spectator). You could also try talking to the officials before matches and explain to them that you are on a restricted diet and wish to bring in your own meal. With diabetics to abunstant these days it seems a tad harsh if they refuse.