It has been hypothesized that television viewing causes obesity by way of o
ne or more of three mechanisms: displacement of physical activity, increase
d caloric consumption while watching or due to the effects of advertising,
and reduced resting metabolism. The results of several recent experimental
studies support the suggestion that reducing television viewing may help re
duce the risk of obesity or help promote weight loss in obese children. One
school-based experimental trial was specifically designed to directly test
the casual relationship between television viewing behaviors and body fatn
ess. The results of this randomized controlled trial provide evidence that
television viewing is a cause of increased body fatness and that reducing t
elevision viewing is a promising strategy for preventing childhood obesity.