"Take care of your body. It is the only place you have to live."
- Jim Rohn
Drink water or other calorie-free beverages when you are thirsty. Soda and other sweet drinks contain a lot of sugar and are high in calories. During workouts, especially extended or intense workouts, Sports Drinks(Gatorade or PowerAde) are a good alternative to water.
Leave your ego at the door, and everyone in your training class will benefit. Ego-less training will provide you with the best results for yourself and your training partners.