Barry Brokaw has always been good at losing weight. Keeping it off has been the problem. The 43-year-old nurse from Superior, Wisconsin, estimates he’s lost—and then regained—100 pounds several times in his life.

Brokaw first took up running as a 200-pound, 18-year-old Army recruit who needed to pass a two-mile fitness test. A few years later, he ran Grandma’s Marathon (in 5:28). The experience didn’t spark a love for the sport, however. Over the next decade, Brokaw viewed running as a calorie burner; he’d lace up only when he felt an urgency to drop weight. Eventually, he couldn’t outrun his gains.

By 2007, Brokaw was a father who felt “a sense of doom” when he struggled to pull his 4-year-old daughter in a wagon. He stepped on a scale and got an error message. He estimates he was 420 pounds; his scale couldn’t produce a reading over 399. To get his weight back down, he cut his beer intake and watched his portion sizes. Within two years, he was 195 pounds and able to run a 1:56 half marathon.

After that race, he scaled back his running—but not his eating—and gained 60 pounds. This time, though, he had a realization: “You don’t finish the marathon, put your hands up, and you’re done,” he says. “You have to think of it as a lifestyle.”

So Brokaw shifted his focus from his scale to his race calendar, making sure it was never empty. He now runs five to six distance events a year and maintains a weight of 160 pounds. In September at the BQ.2 Chicagoland Marathon, he ran a 3:05 personal best.

Brokaw, who averages 50 to 75 miles a week, says running is now “Who I am, on some level.” That mind-set has freed Brokaw from the yo-yo pattern that once plagued him. “Don’t make a bad day a bad week, a bad week a bad month, a bad month a bad year,” he says. “Wake up and reset.”