Weight Watchers vs. fitness centers

Participants who attended Weight Watchers for 12 weeks lost an average of 5 percent of their body weight, or about nine pounds. However, Steve Ball, assistant professor of exercise physiology in the MU College of Human Environmental Sciences, found that a large percentage of the lost weight was lean tissue and not fat.

"Participants' body fat percentage did not improve at all because they lost a much higher percentage than expected of lean tissue," said Ball, MU Extension state fitness specialist. "It is advantageous to keep lean tissue because it is correlated with higher metabolism. Losing lean tissue often slows metabolism. What your body is made of is more important than what you weigh."

The majority of other Weight Watcher studies had not considered body fat percentage change and only focused on body weight.

"This is one aspect of our study that makes it unique," Ball said. "We used a sophisticated measure of body composition – the Bod Pod – to look at what type of weight was lost: lean or fat."

In addition, Ball said the study was novel because Computer Tomography (CT scans) were used to investigate changes in abdominal fat, which is more predictive of cardiovascular disease. Although the fitness center group lost very little weight, they probably improved their health because they lost a significant amount of intraabdominal fat (fat around vital organs). These results imply that exercise may have positive influence on the metabolic syndrome despite the number on the scale, Ball concluded.

Ball also found that group support is very important. Most of the Weight Watchers participants stuck with the program during the duration of the study, while many of the fitness center participants quit.

"These results imply that overweight, sedentary women joining a fitness center with the intent of weight loss or body fat change will likely fail without support and without altering their diets," Ball said. "Nearly 50 percent of people who start an exercise program will quit within six months."

"This study attempted to discover what takes place in the real world when overweight women attempt to lose weight." Ball said. "I think the outcome of the study speaks volumes about the necessity for a multi-pronged approach in order to lose weight, body fat and gain health benefits. I hope that this will be the first in a series of studies investigating commercial weight-loss programs."

The study – "Comparison of a Commercial Weight Loss Program to a Fitness Center" – was published online in the June edition of the Journal of Exercise Physiology.

Source: University of Missouri-Columbia