Just how do they do it: lose double-digit weight and keep it off, especially since so many other people fail at getting slimmer waistlines?

The National Weight Control Registry has your answers -- and strategies you can make part of your own weight-management plan, if you haven't already.

The registry started in 1994 as a way to track the weight management of nearly 5,000 people who have maintained at least a 30-pound weight loss for five or more years.

The average weight loss of registry members? Seventy pounds.

Amount of time they kept it off? Six years.

So they must be doing something right.

Here are their key strategies:

•  They eat a high-carb, low-fat diet. They get most of their calories - from 55 to 60 percent - from from carbohydrates and 24 percent from fat. The rest is from protein.

•  They emphasize "good" carbs found in fruits, vegetables and other high-fiber foods, not carbs based on sugar.

•  They are conscious of calories. Successful maintainers know that total calories count, no matter what diet they follow.

•  They eat breakfast. Eight out of 10 successful maintainers eat breakfast every day, which may help them manage calories during the day.

•  They also eat often - an average of five smaller meals and snacks a day.

•  They self-monitor. Successful maintainers weigh themselves at least once a week, some more frequently, or keep food diaries.

•  They're active - extremely active, 60-90 minutes a day. In addition to carving out time in their busy schedules every day for exercise, they also look for ways to add more activity throughout the way.

Their number one activity? Walking.

•  They eat most of their meals at home, dining out about three times a week.

Failing, but not losing hope

Yet, some other facts about them:

•  Most have failed several times at losing weight and keeping it off.

•  They average going to a fast-food restaurant only once a week.

•  Ninety percent say life is better after their weight loss, because they are brimming with energy, mood and confidence.

•  They are confident in their ability to lose weight and keep it off. They learn that if you can keep the weight off for two years, chances are good you'll keep it off over the long haul.

However, a recent study in April's Obesity Research suggests that people in the registry are eating more fat and fewer carbohydrates.

"Our findings suggest that to successfully maintain weight loss, dieters may be able to vary their diet over time," says Dr. Suzanne Phelan, the study's lead author and psychologist at Brown University Medical School. "Despite the increase in fat intake, the consumption of fat that the participants reported in later years continued to remain within recommended levels and well below the national average.

"However, potentially more troubling is the increase in saturated fat intake - the type most closely linked to an increase in heart disease."