As a sports dietician who has run 15 marathons, I get asked one question more than almost any other: What's the right way to eat before a big run?
The primary advice you've probably heard is that runners should pile on the potatoes and pasta in the days before a marathon. This practice, called "carbo-loading," has long been touted as the way to fuel up for a long-haul race. But does it really work?
In a word: yes. When you eat pasta or potatoes, most of the carbohydrates are stored in your muscles and liver as glycogen – the form of energy your body can access most easily. Glycogen is what fuels your muscles during the race, especially during longer events. Run out of it, and bad things happen. You'll feel sluggish and fatigued. You'll probably slow down, and may want to just give up entirely. Athletes call this sensation "hitting the wall."
Proper carbo-loading can help you plow through that wall. Filling your muscles to the brim with glycogen in the days leading up to an event improves overall performance and delays the onset of fatigue. The trick to carbo-loading is determining when to start and what you need to add to your diet to go the distance.
Who Needs It?
Carbohydrate loading is most beneficial if you're an endurance athlete (marathon runner, swimmer, cyclist) competing at a moderate to high-intensity for 90 minutes or more. If you're taking on a shorter, lower-intensity activity like a relaxed bike ride, strength training, or five- to 10-mile runs, then you can pass on that extra plate of ziti.
The process helps both men and women, but many female athletes complain that eating enough carbs before a race requires them to take in a lot more calories than usual. However, researchers at Baylor University found that for women to reap the most race-day benefits, they only need to increase their total calories by up to 30 percent—from 1800 to 2340, for example—for four days before the starting gun. So even if you're feeling like you're eating too much—that's probably a sign that you're preparing the right way.
How to Do It
During race week, the overall goal is to consume enough carbohydrate to "top off your tank," or store up as much energy (a.k.a. glycogen) as possible. To do this, athletes should aim to take in about 3 to 5.5 grams of carbohydrates per pound of body weight. So for a 150-lb athlete, the goal would be 450-825 grams of carbohydrates per day. While this might seem like a very wide range, it allows room for you to gradually increase your intake as race day approaches. You'll start out with a little extra, and be close to the max the day before it's go time.
A simple strategy for the days leading up to a race is to make sure every meal has some high-carb food in it—bagel, bread, pasta, rice, cereals, fruit, etc. Your goal is to eat items that are high in carbohydrates, moderate in protein (meat, cheese), and low in fat. Here are some examples of meals that meet that bill.
*Breakfast 2/3 cup steel cut oats cooked with 1 cup skim milk ¼ cup dried fruit and 2 tablespoons brown sugar (toppings) 8 ounces 100% fruit juice
*Snack 1 1 cup Apple-Cinnamon Flavored O's cereal with 1 cup skim milk 1 medium banana Water to drink
*Lunch (aim for your largest and most carb-rich meal at lunch the day before a race) 2 cups spaghetti topped with 1 cup tomato sauce and ½ cup steamed vegetables 2 slices whole wheat bread topped with 1 tablespoon vegetable oil spread 12 ounces lemonade
*Snack 2 15 animal crackers dipped in 1 tablespoon peanut butter 1 medium piece of fresh fruit
*Dinner (aim for a light, mild dinner the night before a race) 1 whole wheat pita stuffed with 2 ounces lean deli meat, ½ cup shredded lettuce, 2 slices tomato, 2 tablespoon fat-free honey mustard 2 ounces pretzels 1 cup unsweetened applesauce 16 ounces sports drink
*Approximate Nutrient Analysis (based on USDA Nutrient Analysis Library values) 3100 calories 570 grams of carbohydrate (73% total calories) 90 grams of protein (11% of total calories) 55 grams of fat (16% total calories)