The biggest change the week before the marathon or half marathon is the change in your training schedule, not your diet, according to Nancy Clark, MS, RD. Tapering down your training allows your body to recover. It gives your muscles the opportunity to become fully fueled.

You don’t need to eat hundreds more calories this week. You just need to exercise less. The calories that are normally expended during exercise, say 600 - 1,000 during a workout, will now be used to fuel your muscles. Maintain your diet of 60 - 65% carbohydrate, 15 - 20 % protein, 20 - 25% fat, according to Emily Edison, MS, RD. Don’t load up on foods your body isn’t used to, like white flour low fiber bagels etc. Your best bet is to skip higher fat dressings and butter and add another plain roll to your diet.

Many marathoner’s avoid protein rich foods the days before the marathon. This isn’t necessary, in fact runners burn a little bit of protein along with carbodydrates and fat during an event. You can add a bit of protein to your meals, just don’t have it be the main focus.

You may gain 3-4 pounds as you taper down. This is water weight. For every ounce of carbohydrate stored in your body, you store about 3 ounces of water. You’ll know that your muscles are fueled if the scale goes up a couple of pounds.

The day before your race, it’s important to include carbohydrates in breakfast and lunch. Don’t just rely on a huge pasta dinner. Some good choices are: cereals, bananas, whole grain bagels, multi-grain bread, rice and pasta.

Drink plenty of water and juices. Abstrain from too much alcohol. A beer or glass of wine is okay, especially with a carbohydrate rich dinner. However, too much alcohol will leave you dehdrated. This will impact your performance the next day. Better to be saturated with water than hung over from alcohol.

Nancy Clark’s Good Guide For Marathoner’s, by Nancy Clark MS,RD
Nutrition For Endurance, Emily Edison, MS, RD