Not to be reduntant, but the get off the no carbs bs diet. Carbs are energy! In fact, processed carbs 1/2 hour before workout and even during and after are good, so long as you are putting in work. Eating a Powerbar while drinking Gatorade will only hurt you if you do it while watching Oprah in your Lazy Boy.
Personally, I eat non-processed carbs (whole wheat breads, fruits, etc), during the day. Then, 1/2 hr before class (on my drive there) I eat 1/2 of a Cliff Bar and drink Gatorade. I bring a 50/50 mix of water and Gatorade with me to class that I drink during and directly after. This gives you all the "quick release" carbs you need for instant energy, plus you have "slow release" carbs in your body from eating the whole wheats and fruits (rice is good too, but I f'n hate rice). Drinking some Gatorade afterwards is good too as you need those carbs to replenish your body. Oh, and don't forget protein in every meal. No carb diets are only for inactive people who want a quick fix to there problems. Not for athletes or people serious about making a lifestyle change.
Good luck bro. I love it when people take initiative to get themselves in shape. Don't quit. If you feel like not training for whatever reason, just call yourself a pussy and tell yourself "Man, STFU and Train!".