This is absolutely one of the top 10 topics in sport nutrition. It is so important to have a strategy in place as to how you will fuel and hydrate to prepare for training and exercise. What and when to eat and drink is highly variable and has to be individualized. As an athlete, you have to do a little experimenting to determine what foods and beverages you tolerate, as well as which ones enhance performance. Keeping a journal is a really good idea. It’s important to remember that what works for one athlete may or may not work for another.
Pre-exercise meals should have some carbohydrate, moderate protein, and some fat. The meal needs to be eaten 3-4 hours prior to exercise. Of course, this will be different for early morning workouts. In those instances, the “meal” will be much smaller (like only 100-200 kcals) and consumed 30-45 min prior to workout. Think in along the lines of part of an energy bar or a small bowl of oatmeal. If you aren’t doing an exhaustive workout, the pre-exercise calories aren’t as critical.
At least 2-3 hours before a workout, start hydrating. This can be water, a sport drink, or a fitness water. This will not only keep you hydrated, but allow ample time for emptying from the stomach so that you don’t get cramps. If you are wondering, “Which is better? Water or a sports drink?” Then answer is, “They BOTH hydrate equally well.” Choose the one that works best for YOU. There is a lot of science behind the formulas of the sports drinks, so definitely take some time to educate yourself and to try some of them. They will taste very different when they are consumed during/after exercise, as opposed to just drinking them as a beverage.
The sport drinks, like Powerade and Gatorade, are designed in way that reduces the incidence of cramping, promotes absorption and stimulates the thirst mechanism. They are generally around 6-8% Carbohydrate and use a combination of fructose, sucrose and glucose to promote emptying and speed fluid absorption. Gatorade is 6% and this helps stimulate carbohydrate absorption. Powerade is also 6%. They are both low sodium, with just enough to keep the thirst mechanism going!
Always pay attention to how well hydrated you are. Sweat production can vary depending on intensity, duration, temperature, and humidity. Fluid weight that is lost during exercise is fluid that must be replaced.
The Gatorade website has a tremendous amount of information if you want to check it out.