Rule 5: Go Long
However many miles your longest run is now, extend it once a week. According to the National Runners Health Study, which includes more than 120,000 runners, women who ran the greatest amount of weekly mileage were the leanest.
"There's no question, the more miles you run, the more calories you burn," says Mindy Solkin, a running coach and founder of The Running center in New York City. You burn roughly 100 calories per mile when running (depending on your weight), so if you go for a five-mile run, you'll burn 500 calories.
Rule 6: Team Up
A running coach and a personal trainer helped Davidson meet her goals. For other women, a support team may include a nutritionist or running partner. Check out peertrainer.com for an online weight-loss and exercise-support group.
Nan Howard's 53-pound weight loss journey began in 2007 at a weight loss support group meeting where other members encouraged her to walk for exercise. The North Carolina working mom slowly turned her walk into a run, and she began participating in local 5ks. Now she's encouraging other women in the group to start running.
Rule 7: Increase Intensity
A study conducted in 2006 at the University of Guelph in Ontario, Canada, found that interval training--bursts of speed within an aerobic workout--burns fat and improves fitness more quickly than constant, moderately intense exercise. Researcher Jason Talanian recommends mixing interval training into your routine once or twice a week.
Rule 8: Crunch All the Numbers
Harvard weight loss expert Dr. George Blackburn asserts in his new book, Break Through Your Set Point, that people who weigh themselves daily are significantly more successful at keeping off excess weight. But also measure and record your changing body mass index (18.5 to 24.9 is considered normal), body fat percentage (aim for 14 to 24 percent), cholesterol levels (less than 200 total is desirable), blood pressure (at or below 120/80), clothing size and training distances and times. If after making positive changes you're still having trouble losing weight, ask your primary care physician to crunch another number, your TSH level. Hypothyroidism can cause weight gain.
Rule 9: Keep a Food Diary
Solkin tells people to keep a daily log of what they eat. When you see how that soda or bag of chips adds to your total, it might be easier to eliminate. In a recent study funded by the National Institutes of Health, participants doubled their weight loss when they kept a food log. To track your habits, use myfooddiary.com.
Rule 10: Train for Something Bigger Than Weight Loss
There's no better motivation to maintain an exercise schedule and eat right than a race date. For Howard, the recent shift from seeing herself as "someone who runs" to being "a runner" has been a revelation.
"People say 'What are you doing? You look so great,' and I say, 'I run four to six days a week,' " she explains. "You say that enough, and you start feeling like a runner."