Evidence suggests that watching television is associated with changes in energy intake that may contribute to weight gain and obesity. Studies performed in laboratories tend to show that subjects who watch television increase the amount of food they eat during a test meal (by 11.5 to 71 %). However, the data is not conclusive and other factors appear to be involved. Although the mechanisms are not fully understood, a number of theories have been suggested to explain the association between television watching and weight gain. Television may cause overconsumpton of calories by distracting the viewer from moderation, may cause emotional changes in the viewer, or may encourage eating through the use of advertisements. In addition, watching television may be associated with more sedentary lifestyles, indicating that long-term television watching might result in a positive energy balance.
For example, in one study1, 48 adults with a body mass index of between 20 to 35 kg/m2 had their energy intakes recorded while watching television with advertisements, watching television with no advertisements, while reading and a control which involves just eating. The results showed that while the amount of calories consumed between the various groups did not vary, but there was a correlation between the recollection for television advertisements and the energy intakes and body weight of the individuals. Memory tasks involving lists of advertisements that were (50 %) or were not (50 %) in the television schedule shown were used to assess the recollection of advertisements. Advertisement memory was quantified by the amount of advertisements the subject had recall of. The memory of advertisements was associated with greater energy intake and body weight. The researchers also reported that distractibility was associated with bodyweight.
These results are interesting because they suggest that those individuals that have an ability to recall advertisements may be more susceptible to overeating and body weight gain. Although the results do not show a direct relationship between watching television and overeating, this has been demonstrated in previous studies. These results therefore provide additional data to suggest that weight gain or increased energy intakes in those that watch television is a multi-faceted process that may involve both short-term overeating effects, long-term conditioning effects, as well as other factors. The study also tested the distractibility of participants and found that there was an association between distractibility (particularly men) and body weight. These findings support the previous research that has found associations between attention deficit hyperactivity disorder (ADHD) and being overweight or obese; with ADHD being more common in males.
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