Harsohena Kaur, MD, MPH
Obesity is the epidemic of the new millennium. Over the last two decades the proportion of children and adolescents who are overweight has steadily risen. Given that our genetic structure has not changed in this interval, attention is being focused on the environment as the cause, because it has surely changed over the last two decades.
Advances in food processing technology have led to the wide-spread availability of inexpensive food and portion sizes have ballooned. Thanks to automation, we use less energy to do our household chores (e.g., use of washing machines, dishwashers, vacuum cleaners, powered lawn mowers), and to transport ourselves (e.g., riding the car instead of walking, elevator use instead of climbing stairs, etc.).
Schools, like jobs, have also become increasingly sedentary with more children spending more time at their desks and less in physical education classes or playing during recess. We are eating larger portions, eating out more often, drinking vast quantities of sugared beverages, using less energy to do activity (both at work and at home), and spending more leisure time on sedentary activities such as television and video games. The combination of all these factors has led scientists to term our modern lifestyle as a "toxic environment" that promotes obesity.
Television viewing is of particular importance as it is the predominant sedentary behavior among American children, second only to sleeping. Watching more television seems to be linked to being overweight, but it has not been clear whether weight gain occurs due to watching more television or that overweight children watch more television.
A recent study in the Journal of Pediatrics assessed the amount of television watched and the weight status at one point in time and then a follow-up weight status three years later. The authors indicate that watching more television subsequently leads to larger weight gain. In addition, watching more than two hours of television a day was responsible for causing a fifth of the normal weight children to become overweight three years later. The data provide support that television is a causative factor for obesity.
Although the exact reasons why television promotes obesity are unclear, there is some evidence that television time displaces time spent in physical activity and also leads to increased snacking and consumption of nutritionally poorer diets. Children are influenced by the numerous advertisements for food, most of which are for high sugar foods or fast foods, and so increase their requests for and consumption of such items. In addition, children are likely to overeat when they eat while watching television as they are focused on the programming and less aware of their internal cues.
Given that television is here to stay and does provide some positive value, its health impact can be mitigated by staying within the guidelines recommended by the American Academy of Pediatrics and ensuring that children watch less than two hours of television a day.
Dr. Harsohena Kaur is a faculty member in the Department of Pediatric, Kansas University. In addition to seeing patients and teaching, Dr. Kaur conducts clinical research in health behaviors in childhood and adolescence especially nutrition, physical activity and sedentary behaviors and their impact on obesity.
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