This study explored the hypothesis that TV viewing and fast food eating may contribute to obesity in the United States. The
data for women were generally consistent with the hypotheses. Hours of TV viewing per day and meals eaten at fast food restaurants per week were both positively associated with body mass index cross sectionally. TV viewing also predicted weight gain in high-income women. The finding that energy intake and percentage of energy from fat were also positively associated with TV viewing and fast food eating would seem to strengthen the inference of causation by identifying a plausible intervening mechanism. The associations between TV viewing and obesity seen for women in this study are consistent with previous research in adults. The observation of a stronger link between TV viewing and obesity in low-income women is also consistent with the only previous study, in children, to examine the issue.'° To the best of our knowledge, the findings relating fast food eating to weight are new, as are those showing that fast food eating and TV viewing are correlated with dietary intake. Two negative findings in this study merit further comment. First is the lack of
an association between TV viewing or fast food eating and body mass index in men. One possible explanation is that these men were a special group (i.e., volunteers for a study of weight gain prevention). Another is that the relationships between TV viewing, fast food eating, and weight are not the same in adult men and women, perhaps as a result of differences in occupational or social roles. The second negative finding meriting comment is the failure to find a relationship between exercise and TV viewing, even though exercise has typically been thought to be the mediating link between TV viewing and body weight.23 One possible explanation for this apparent discrepancy is that the exercise measure used here, which assessed the frequency of exercises sustained for 20 or more minutes, may not have been sensitive enough to detect the
types of activities most likely to be affected by TV viewing (i.e., short bursts of relatively low-intensity activities such as working around the house). Another is that the relationship observed between TV viewing and body weight is, in fact, mediated by eating rather than exercise. Strengths of the present investigation include a simultaneous examination of the
associations between both fast food eating and TV viewing and body weight in a relatively large and diverse sample of adults. Generalizability is limited by the fact that the sample was composed of volunteers for a weight gain prevention study and thus is not representative of the general population. In addition, our measures of TV viewing and fast food consumption, while similar to those used by other investigators, were relatively unsophisticated and of unknown validity. The time interval covered by the prospective analyses was also fairly short. Nevertheless, the findings suggest that further study is warranted of how changes in population exposure to fast foods and TV may be related to secular trends in obesity prevalence in the United States.