Eating your exercise calories - good explanation!

Eat Smart Before Exercising - article from prevention.com

Why food is so important to a good workout?

By Liz Applegate , Liz Appletgate, Ph.D., a Runner's World magazine columnist and author, is on the Nutrition Department faculty at the University of California, Davis.
Like many people, you may think that eating before exercise is self-defeating. After all, if you work out for weight loss, why would you want to counteract all of those burned calories by filling your body with food?

Well, there are plenty of reasons. Here are the most important ones:

You'll actually burn more calories by eating before you run, swim, walk, or lift weights. When you don't eat before you exercise, many of the reasons for working out--conditioning, fitness, building muscle mass and strength, weight loss--go out the window. That's because your body turns to muscle protein for fuel when it doesn't have enough carbohydrate to burn. If you start your exercise routine well-fueled, your body will burn a combination of the carbohydrate stored in your muscles and the fat stored in your fat cells.

You'll be motivated to get out the door. If you exercise during your lunch break or after work, you're probably all too familiar with the excuses "I'm too hungry" and "I'm too tired." A healthy snack will eliminate those excuses.

You'll have the endurance to lengthen your workout. How many times have you stopped exercising because you felt dizzy, shaky, or just plain pooped? That's because you didn't have enough calories to go the distance.
You'll perform better. Stocking up on calories delays that burning feeling in your muscles, which will help you run, cycle, walk, or swim faster and for longer periods of time. Test subjects who ate before exercise also reported feeling better and rated their efforts as less rigorous than those who had fasted beforehand.

Your body needs fuel to keep your heart pumping and your brain buzzing even when you're not pounding the pavement. Have you ever felt light-headed when you haven't eaten for several hours? That's a sign that your brain is suffering from less-than-ideal fueling conditions. The bottom line is that you need to eat every 3 to 5 hours to maintain basic body functions.

Eating smart before a workout--particularly food that supplies loads of carbohydrate--provides a whole host of benefits. Your muscles receive an infusion of energy to help maximize the results of your workout, and your entire body (especially your brain) gets the fuel and nutrients it needs for daily living.
What, When, and How Much
Here's a look at specific eating guidelines for preworkout fueling.

Eat 2 to 4 hours before a workout. This may mean planning your meals at different times to accommodate your exercise and weight loss schedule. For example, you may eat lunch at 2:00 p.m. so you can work out at 6:00 p.m.

Eat 400 to 800 calories at your pre-exercise meal. This amount should fuel your workout without making you feel sluggish or full.

Choose high-carb foods that are low in fat and have a moderate amount of protein. A whole grain bagel topped with tomato slices and low-fat cheese, or breakfast cereal and fruit with 2% milk or soy milk, are both excellent choices.

Drink at least 10 ounces of water or sports drink 2 hours before you exercise. This helps offset sweat loss during your workout. The 2 hours gives your kidneys time to rid your body of any excess fluid.