Marathoning and Weight Loss
Caloric Requirements of Marathon Training and Running
Few marathon runners are obese because long distance running and marathon running and burn so many calories. How many calories are required to run marathons?
Calories Burned Running
Obesity runs rampant in the developed world, but marathon runners and other serious long distance runners are seldom obese or overweight. Their secret? The extreme caloric requirements of training for and running marathons.
A 150 pound person burns about 100 calories per mile running. This number is relatively independent of pace, but it does depend on body weight. Though not exact, it's a good round number for approximate calculations.
Marathon Run
A marathon is 26.2 miles. So, a 150 pound runner burns about 2600 calories running a marathon. This figure is more than a full day's basal metabolism rate for an inactive 150 pound person.
A pound of fat has 3500 calories, so this marathon runner burns about 3/4 of a pound of fat in a few hours. A heavier runner might burn enough calories to lose a full pound.
Most runners will not actually lose this much running a marathon because they consume many calories the nights before and after the marathon to have enough energy. It is also difficult to run more than a few marathons a year. The real weight loss comes from the marathon training.
Elite Marathon Training
Elite marathoners typically run 100 to 150 miles per week. At 100 calories per mile, that's about 10,000 to 15,000 calories or 3 to 4 pounds of fat per week. These runners of course, don't lose 3 to 4 pounds a week because they, of necessity, have rather large appetites. It is however difficult to eat enough to gain weight while burning this many calories. Elite marathoners are usually quite slender.
Ordinary Runners Training for Marathons
An ordinary non-elite runner just wanting to finish a marathon or to beat last year's time, does not run as much. A basic level for these runners might be 50 miles per week.
A 150 pound runner will burn an extra 5000 calories per week (700 per day) running this far. That's just under a pound and a half of fat per week.
A sedentary person who suddenly starts running 50 miles per week without increasing his/her caloric intake would lose about 1.5 pounds per week.
Of course that won't happen. A previously sedentary person should not start running at this level. If you are sedentary and want to start running to lose weight, start slowly. Start walking, gradually add running, and build by no more than 10% per week.
Realistic Weight Loss Potential
A runner training for a marathon will eat more than a sedentary person. It is still possible to gain weight while running 50 miles a week. A daily box of donuts and banana split will do the trick.
This runner will however not gain as much as an inactive person with the same eating habits. Marathon training allows runners who are already at their ideal weight to get away with a few extra indulgences.
A marathon runner who needs to lose weight can do so more easily than an inactive person. Running 50 miles a week burns an extra 700 calories a day. This runner can eat 200 calories per day more than an inactive person (not dieting) and still have a daily 500 calorie deficit. That's losing about a pound a week, while still eating fairly heartily. This runner can eat an extra 500 calories a day and still lose a pound every 18 days - about 1/3 of a pound a week.
Overweight marathon runners are rare because long distance running at the level of training for marathons burns so many calories. Long distance marathon training will control weight even with occasional (not too often) hearty meals.
For the less ambitious, walking or running less extreme distances combined with a sensible diet can still produce significant weight loss.
