Drinks that contain caffeine and alcohol have dehydrating effects, which offer no benefits to a person who works out regularly or an athlete in training.

If you eat food high in sugar (such as a candy) 30 to 60 minutes before working out, it may actually have a negative effect on your performance. The short-term energy boost may be followed by temporary low blood sugar, which limits the brain’s ability to use its fuel (calories) to boost muscular function and mental drive. Premature fatigue results.

During your workout you use muscle gylcogen stores to fuel the activity. These stores must be replenished for optimal muscle recovery and repair. A snack that combines a moderate source of carbohydrates with a small protein source is your best choice. Your post-workout snack should be eaten within an hour of finishing your workout in order to maximize the recovery.