Not All Weight Loss Is Created Equal

Study finds Weight Watchers participants lost more weight than fitness center users, but the wrong kind.

BY DANIEL S. LEVINE
The Journal of Life Sciences

Just in time for bikini season, new research out of the University of Missouri answers the question of whether Weight Watchers or a gym membership provides better health benefits.

To answer the question, Steve Ball, an assistant professor of exercise and physiology in the university’s College of Human Environmental Sciences used sophisticated methods to measure body composition. This included the use of a “BOD POD,” an egg-shaped chamber in which participants sit to measure body volume through air displacement, and CT scans to determine changes in abdominal fat, which is more predictive of cardiovascular disease.

The study, published online in the June edition of the Journal of Exercise Physiology is believed to be the first to use sophisticated methods to measure body composition to compare these two weight loss measures.

Ball found participants in the study who attended Weight Watchers for 12 weeks lost an average of 5 percent of their body weight, or about nine pounds. But a large percentage of the lost weight was lean tissue and not fat. He found that despite the weight loss, the participants’ body fat percentage didn’t improve.

"It is advantageous to keep lean tissue because it is correlated with higher metabolism,” he said. “Losing lean tissue often slows metabolism. What your body is made of is more important than what you weigh."

Most studies that have looked at Weight Watchers have focused on body weight and had not considered body fat percentage change, Ball said.

By comparison, the group of participants that were assigned to the fitness center lost very little weight, but Ball said they probably improved their health because they lost a significant amount of intraabdominal fat (the fat around vital organs). He said that implies that exercise may have positive influence on the metabolic syndrome despite the number on the scale.

One important difference between the too groups of participants Ball discovered was that the Weight Watchers participants stuck with the program during the duration of the study, while many of the fitness center participants quit. Nearly half of people who start an exercise program will quit within six months. Ball said women seeking to lose weight or change their body composition by joining a gym will likely fail without support and altering their diets.

"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," he said.