If you want to lose weight, the solution seems simple: Slip on your sneakers to put in a few laps at the track or a few miles on the treadmill. While this is intuitive, it's not necessarily effective. Running can be a helpful part of your weight-loss plan, but only if you have an overall plan. Otherwise, you may actually find yourself packing the pounds on.
In Theory
In theory running should help you lose weight. This is because burning excess calories will help you to burn fat, and running is a great calorie burner. You need to burn an extra 3,500 calories to shed a single pound, so in theory you'll lose a pound for every additional 3,500 calories you burn off running.
Calorie Burn
The calorie burn from running will vary depending on your weight. A 160-pound person will burn 126 calories per mile. At that rate she'd have to log almost 27 miles of running to burn a pound of fat. The more you weigh, the higher your calorie burn will be. A 250-pound person will burn approximately 198 calories per mile, which means she'd have to run slightly less than 18 miles to lose a pound of fat.
The Reality
According to Eric Ravussin, an exercise researcher with Louisiana State University, "In general, for weight loss, exercise is pretty useless." This is because while it burns off calories, it has another unintended effect: It increases your appetite. If you burn off 500 calories running, it won't do anything for you if you eat them back. In fact, you will gain weight if your increased appetite causes you to eat back more calories than you burned off.
The Solution
The solution to losing weight lies in controlling your calorie intake. The McKinley Health Center recommends creating a daily calorie deficit of between 500 and 1,000 calories by increasing your physical activity and decreasing your caloric intake. For instance, if you burn 500 calories per day running and reduce your caloric intake by 500 calories per day, you'll create a weekly calorie deficit of 7,000 -- equivalent to 2 pounds of fat.