This is part four in an on-going series focused on helping first time runners and racers.
Protein can be broken down into sugars for use in the body under extreme circumstances, so let's keep the focus on carbohydrates. Carbs are stored as glycogen in the muscles and liver. You can store around 2000 kcal as glycogen. This gives you enough energy to run or walk around 20 miles.
Many of you may have heard of "carb-loading". This is great to do if you are running longer than a half-marathon. Some marathon runners will indulge in carb-loading up to three days before a race. This simply means increasing your carb intake while cutting back on running, thereby reducing glycogen consumption.
Within six hours of the race, you should eat high glycemic index foods such as bread, raisins, and sugar to increase your blood sugar and top-off your body's glycogen.
It takes about 30 minutes for the carbs to reach your bloodstream, so during the race, you need to start eating before you feel tired! There are these amazing gel packs that you can stick away in your pocket. Each pack contains around 20g of carbs! It's best to take them at water stops because they are so concentrated. If you decide to go with the gels, make sure you try training with them on your long runs so you can make sure they don't upset your stomach. Check the expiration date! I had a horrible experience with old gel during a marathon!
Water and knowing how much to take in is also very important. There is such a thing as too much water. Taking in too much can even be dangerous! Hyperhydration, or "water intoxication", can dilute sodium levels in your body in a condition known as hyponatremia.
So, do not drink obsessively several days before a race. Drink when your thirsty. During a race, again, drink when you are thirsty. Water, sugars, and electrolytes will help you perform, but don't force yourself to drink. If you get a sloshy feeling in your stomach or feel queasy, drink less. Finally, you can try drinking sports drinks instead of water during a race to help with electrolytes.
Listen to your body! Run long and health!