“Obese children who
become obese adults
have a very difficult
time losing weight
and maintaining a
normal weight; only
a very small
successful in the long
run … the best hope
is to catch kids early
and try to prevent
them from becoming
see the light
Leonard Epstein, research team study how reinforcing
behavior can control kids’ weight
By S. A. Unger
Epstein says obesity carries the same risks for children as it does for adults: an increase in health problems that include diabetes mellitus, hypertension and high cholesterol. Obese children are also at higher risk of becoming obese adults.
"Obese children who become obese adults have a very difficult time losing weight and maintaining a normal weight; only a very small percentage are successful in the long run," he says. "So most researchers feel the best hope is to catch kids early and try to prevent them from becoming overweight adults."
As part of their ongoing effort to devise ways to "catch kids early," Epstein and his group are conducting a study aimed at better understanding how sedentary behaviors can be modified to treat and prevent obesity in children. In work funded by a $1.1 million grant from the National Institute of Child Health and Human Development (NICHHD) of the National Institutes of Health, the researchers are interested specifically in discovering ways to modify sedentary behaviors that are especially popular among today's children: watching television, playing video games and surfing the Internet.
In describing the stairstep approach he and his group have taken over the past 20 years to arrive at their current focus on sedentary behaviors, Epstein explains that the team's first studies-begun in the early 1980s at the University of Pittsburgh-demonstrated the efficacy of treating a child and his or her family together, versus treating the child separately. From there, Epstein's group focused its attention on trying to understand the role of physical activity in treating obesity. A review of the literature suggested that lots of people who begin exercise programs do not maintain them, he says. As a result, his group developed the idea of "lifestyle exercise."
Instead of trying to get people to adhere to a high-intensity exercise program, lifestyle exercise encourages changes in everyday behaviors, such as parking farther from a store entrance and walking. In the early 1980s, Epstein's group completed the first randomized study done on a lifestyle-exercise program and demonstrated that this approach works better than traditional exercise.
By the mid-1980s, Epstein's research had resulted in the creation of innovative exercise and diet models specifically geared to treating obesity in the pediatric population. "About that time, however, we started to recognize that even though lifestyle exercise and diet were very useful, lots of kids still preferred being sedentary, so then we started to look at the competition-and the competition, of course, was television," recounts Epstein.
This realization was based on pioneering work being conducted at that time by two Harvard researchers, William H. Dietz Jr. and Steven L. Gortmaker, who "were the first to effectively argue that sedentary behaviors-television viewing, in particular-were a risk factor in the development of obesity," Epstein says.
Based on Dietz and Gortmaker's studies, Epstein became interested in the idea of behavior-choice theory, and in the early 1990s, he and his group began a series of studies aimed at better understanding how sedentary behaviors can be modified within the context of this theory to treat and prevent childhood obesity. Again, the sedentary behavior the researchers were particularly interested in studying was television viewing.
"Behavioral-choice theory recognizes that kids have a choice between two incompatible behaviors-they can either be active, or they can be sedentary," explains Epstein. "Therefore, we started to look at understanding how people allocate choice-how they decide to do things-and in working with behavioral-choice theory, one of the obvious things suggested by it is that if two things are incompatible, you can either reinforce the one you want, or you can reduce access to [the other]."
Subsequently, Epstein set up a study comparing weight loss among three groups: one reinforced for an increase in exercise, a second for a decrease in sedentary activity, and a third for a combined approach. To reinforce behavior, contracts were set up between the children and their parents that enabled the children to earn points toward rewards that were activity-based, as opposed to money or food; for example, going to the zoo with their parents.
The results of the study, published in Health Psychology in 1995, showed that the children who were reinforced for being less sedentary-e.g., less television and fewer computer games-had a bigger weight loss than the children who were reinforced for increasing their physical activity.
This study, which was the first to manipulate access to television, suggested "that at least this was an alternative approach to trying to work on getting kids to be more active," says Epstein. In an effort to replicate these findings and better understand how the children made their choices, Epstein and his group recently completed a study titled "Exercise in the Long-Term Control of Childhood Obesity," which was funded by a $1.1 million grant, also from the NICHHD. Participants in this study were randomized to either increase physical activity or reduce sedentary behavior and, in addition to keeping a log on their exercise and food intake, they wore a beeper-size device called an accelerometer that provided the researchers with data about caloric expenditure.
"We found that the group that reduced sedentary behavior had substantial increases in weight loss and improvements in fitness that were maintained over the two years we followed them. We also found that in the kids who reduced their sedentary behavior, about one-third of the time they substituted the behavior with physical activity, which is exactly what we wanted."
Epstein emphasizes that the children were not told what they had to do; instead, they were being rewarded for choices that freed up time for them to fill any way they chose. "Everybody likes to choose what they're going to do, and they are much more likely to change a behavior if they think it's their choice," he says.
In 1997, Epstein and his group conducted a study that confirmed this supposition: "We got much better results for reinforcing children's behavior than restricting it," he says.
Two years ago, with these preliminary results in hand, they began their current study, the goal of which is to look at different ways to reduce television viewing that translates into different kinds of outcomes. "We know that reducing a broad constellation of sedentary behaviors-especially TV-is useful in treating obesity," says Epstein. "The study we're currently conducting is designed to identify specific techniques we might use to do that."
S.A. Unger is editor of Buffalo Physician.