Calories and Long Distance Runners

You might think a long-distance runner who trains for the 26.2-mile marathon distance or farther can eat anything he wants and not gain weight. Traversing dozens of miles in a week does burn calories, but it isn't an excuse to gorge on junk food. Consuming the right kind of calories is essential to avoid weight gain, which can negatively affect performance. Fueling with adequate calories before, during and after a run can also be tricky -- eat too little and you lose energy, but if you eat too much, you may feel weighed down. Understanding a distance runner's calorie burn and needs will help you make the best calorie choices possible.

Running is one of the most effective calorie-burning exercises. A 155-pound person running at a 7-minute-per-mile pace burns approximately 539 calories in 30 minutes. If he goes at an elite runner's pace of 6 minutes per mile, he'll burn 614 calories. Even a slower 11.5-minute-mile pace yields a 335-calorie burn in 30 minutes. Novice distance runners usually train between 20 and 40 miles per week, while elites cover 50 to 100 miles. A 155-pound runner can thus burn between 2,900 and 12,000 extra calories weekly. Smaller runners will burn less and larger runners will burn more.

For novice runners in the first weeks of long-distance training, the extra 2,500 to 3,000 calories burned weekly may be easy to replace. As you progress to more mileage and faster tempos, getting enough calories can be tricky. Failing to fuel can cause unwanted weight loss, slower recovery and energy dips. In the March 2010 issue of "Today's Dietitian," registered dietitian Janice H. Dada recommends distance runners take in 19 to 26 calories per pound of body weight. If you are sidelined with an injury, you should eat a more moderate amount to match your daily burn rate -- but don't starve yourself. Your body needs the nutrients to heal quickly so you can hit the road again soon.

Your daily calories should roughly be composed of 55 to 60 percent carbohydrates, 20 to 35 percent fat and 10 to 25 percent protein. Dada notes that a distance runner should consume between 3.2 and 4.5 grams of carbohydrate per pound of body weight during training. For a 155-pound person, this amounts to between 496 and 698 grams daily. In the days leading up to a long run or big event, aim for the higher end of this range. Protein needs are 0.55 to 0.64 grams per pound of body weight, or 85 to 99 grams for the 155-pound example. Carbohydrates provide the primary source of fuel for your muscles, while protein helps with muscle repair and recovery. Fat provides a dense source of calories.

Two to three hours prior to a long run, consume a carbohydrate-rich snack containing 400 to 800 calories to provide you with adequate energy. You need additional fuel during your run if your training or race will last longer than 90 minutes, the amount of time your stored glycogen, or energy, lasts. Choose high-carb energy foods, such as gels, sports drinks, dates, jelly beans or bars, and consume approximately 0.32 to 0.45 grams of carbs per hour on your long run. Every gram of carbs has 4 calories, so if you are a 155-pound person, every hour you need 50 to 70 grams of carbs, or 200 to 280 calories' worth. After a long run, a snack consisting of a ratio of carbs to protein of 4-to-1 will help restore glycogen and enhance repair and recovery of muscles. This snack should contain between 100 and 400 calories, depending on how many you burned during your run and if your next meal is hours away.