Individuals who are most successful at long-term weight loss burn an average of 400 calories per day through exercise in addition to keeping their caloric intake in check, says the National Weight Control Registry (NWCR).

According to the scientists who maintain the registry, walking is the most popular form of exercise among the more than 2,000 successful "losers" being tracked. Since most individuals burn about 100 calories per mile walked, these folks are hoofing it about four miles per day.

The former heavyweights being tracked by the NWCR are no dieting lightweights. To qualify for the registry, individuals must have lost a minimum of 30 pounds and kept it off for at least a year. But according to the registry researchers, the average "loser" on the registry has shed 60 pounds and kept it off for five years.

So, no more excuses that you don't have time for the gym. Slap on those shoes and start walking!