For the 90 million or so American adults who are obese, shedding the pounds might seem like an impossible feat. That’s why researchers turned their attention to those who were successful. Study participants who had lost 30 or more pounds — and kept it off for at least a year — revealed the key to maintaining weight loss is the consistency of their moderate- to vigorous-intensity workouts. Researchers compared individuals who usually exercised at the same time of day with those who had more sporadic workout habits.