Back in 1994, Dr. Rena Wing, a behavior psychologist from Brown University, and Dr. James Hill, a professor at the University of Colorado Health Science Center, jointly established a database composed of successful losers; people who had lost a substantial amount of weight and were able to keep it off. The two founders hoped that by studying this population they could uncover their secrets.

The criteria for inclusion into the National Weight Control Registry database are simple. All you need to do is lose at least 30 pounds, keep it off for 12 months or longer. Membership is currently ongoing and has now exceeded 5,000 individuals.

Not surprisingly, most of the enrollees up until 2003 have turned out to be middle-aged white females. The mean weight loss was an astounding 66 pounds, kept off for a mean of 5.5 years!

In studying how the group lost weight, Wing and Hill found that nearly 9 out of 10 used some type of dietary change in combination with exercise. Ten percent of the group used just diet, while only 1 percent used just exercise.

It is interesting to note that they could not identify one specific diet used by the group that was the most successful. Some enrolled in a formal program, some did it on their own. Others counted calories, while a few counted fat grams. Use of meal replacements, exchange diets, and restricting certain foods were all reported as a means for success.

Wing and Hill identified 4 common behavioral characteristics among the group that they believed contributed to successful weight maintenance.

1 Low fat, high carbohydrate diet. When surveyed, members of the Registry reported a diet in which 23-24 percent of total calories came from fat, allowing for a reasonable intake of some healthier versions.

2. Eating breakfast. Roughly 8 out of 10 reported eating breakfast regularly. Most said they ate breakfast every day without exception.

3. Regular weigh-ins. About three quarters of the group said they weighed themselves at least once week. Some weigh themselves daily. Hill believes that regular weigh-ins serve as an early warning signal, and many of the subjects have a strategy ready to deploy in the event they gain a few pounds.

4. Plenty of exercise. Women estimated an average daily expenditure of 2,500 calories. Men estimated burning 3,300 calories per day. That is roughly 60-90 minutes of moderate intense exercise, such as brisk walking, every day of the week (ACCUMULATED THROUGHOUT THE DAY, not all at one time).

The authors acknowledge potential flaws in their research. There is no control group, and subjects are self selected. The possibility exists of biological differences between these people and others who are having trouble maintaining weight loss.

Despite the drawbacks, the information they have uncovered is useful. The database is large enough to provide some pretty convincing evidence of what works for keeping weight off for a large number of people.