Refuel on Your Long Runs

26.2 miles is a long way to go without eating. A 120-pound woman burns about 2,500 calories running a marathon – equivalent to more than 11 plain (2 oz.) donuts. A 160-pound man burns about 3,300 calories – or about 15 plain donuts' worth. The occasional orange section that's typically offered on the course doesn't put much of a dent in that deficit.

While nobody would suggest you eat a dozen donuts during a marathon, you'll probably find the last few miles of the race easier if you've eaten something during the earlier miles. But it's not a good idea to wait until your race to discover how your stomach will react.

Practice eating during your training runs. Many long-distance runners use energy gel. It's readily absorbed, and generally sits easy on the stomach. Some runners prefer raisins or other foods that are easy to carry and pack a decent energy punch.