Habits are hard to change, especially those relating to diet and exercise, as anyone who has ever tried to lose weight can testify to. Many commercial weight loss programs claim to help, but until now their success rates have not been rigorously evaluated, even though they often boast success stories in their promotions. Scientists from universities across the United States recently compared weight loss in people participating in a commercial program with people attempting to lose weight on their own. Their report appeared in a recent issue of the Journal of the American Medical Association.

Group vs. solo

The study included 400 adults with a body mass index (BMI) between 27 and 40. (A person with a BMI over 25 is considered overweight; and a BMI over 30 indicates obesity.) The volunteers were divided into either the "self-help" group or the "commercial program" group. Those in the "self-help" group met several times with a dietitian who provided printed materials about healthful eating and exercise. They were also directed to resources - libraries, health organizations, websites - that offered free weight control information.

Volunteers assigned to the "commercial program" were given vouchers to attend meeting at Weight Watchers, a program that includes eating and exercise plans designed for gradual weight loss. At the weekly Weight Watchers meetings the volunteers were weighed and given educational materials and social support.

Weight loss was monitored every three to four months over a 2-year period. The researchers also assessed other health improvements that are often associated with losing weight, such as cholesterol and blood sugar levels, blood pressure, and perception of overall quality of life.

Group dieters have an edge

At the end of the 2-year study, about half of those who attended Weight Watchers meetings had been able to lower their BMI by at least one number - a benchmark that health officials say indicates a significant weight loss. On the other hand, only 29% of those in the self-help group were able to lose that much weight.

Not surprisingly, those who attended Weight Watchers meetings regularly lost more weight than those who attended meetings less often. Regardless of which group they were in, weight loss improved the volunteers' health profiles and self-reported quality of life.

Advice to consumers

This study reports on only one particular program - Weight Watchers - and it can't be assumed that all commercial programs will contain the same components. It's not clear which part of the Weight Watchers program was responsible for the successes - the educational materials, the food plans, the weekly monitoring, or support.

However, the volunteers in this study did appear to benefit from the ongoing personal attention and feedback available at group meetings. This underscores the point that in any challenge - and changing eating and activity habits is a big one - success may be easier with continual support than trying to go it alone.