Relevant story from this week's LAT health section:

Based on data from more than 7,000 people, Wing says there are few similarities in how people lose weight. But those who succeed in maintenance sing the same song.

Instead of trying to eat less for the rest of their lives to bridge the energy gap, these people exercise more. They typically spend an hour or more each day in aerobic exercise and strictly limit time spent watching television.

Physical activity, in ways that researchers don't really understand, influences some of the biological systems that promote weight regain, encouraging the body to become more sensitive to leptin and insulin, for example.

"Everyone thinks exercise is about burning calories," Fujioka says. "But you are actually returning the system to more like what it should be. Things start working again."