Childhood Obesity Doubled in a Generation
The number of
obese children has grown dramatically in the past two decades, more
than doubling in one generation, a new study has found.
which was conducted by researchers from the University of Buffalo, The
Johns Hopkins University, the National Cancer Institute and the Centers
for Disease Control and Prevention, looked at the rate of obesity among
children between the ages of 8 and 16. One of the factors in the
startling increase: television-watching, researchers say.
to be a national campaign to increase the opportunities for boys and
girls to participate in lifetime physical activities," said Dr. Carlos
Crespo, UB associate professor of social and preventive medicine and
first author of the study. "At the same time, we should have a national
health objective of limiting children to two hours or less of
television-watching a day."
analyzed data from 4,069 children who took part in CDC's Third National
Health and Nutrition Examination Survey, conducted between 1988 and
1994. They then assessed the relationship between television-watching,
energy intake, physical activity and obesity.
received a physical exam and answered a number of questions about their
lives, including how much and what kinds of food they ate during the
previous 24 hours, how many hours of television they watched, and how
many times a week they were active enough to breathe hard or work up a
Among the findings:
- Nearly half of U.S. children between the ages of 8 and 16 watch more than two hours of television a day.
Sixty-five percent of black children and 53 percent of Mexican-American
children watched more than three hours of TV a day, compared with 37
percent of white children. Seventeen percent of black children watched
for five hours or more a day.
- The prevalence of obesity increased as hours of TV-watching increased.
number of calories consumed increased as the number of hours of
TV-watching increased; total calories were higher for boys than girls.
- Only a little more than half of the children engaged in physical activity five or more days a week.
showed a closer association between television-watching and obesity
than between TV-watching and physical activity, Crespo said, because it
was hard for children to accurately recall how much exercise they took
"If you ask
how many hours they watch TV, they can do that quickly," Crespo said.
"Physical activity is harder to quantify. Nevertheless, if they're
watching TV, they aren't exercising."
The lack of
physical activity was particularly evident for girls between 14 and 16
years old, when less than one-third are active, he said.
For many girls, particularly those living in "marginal" neighborhoods, the issue is safety, he noted.
'bad' neighborhoods, especially girls, are told to go directly home
from school and stay there," Crespo said. "Boys have more freedom to
roam the neighborhood and can be more active. Many kids are home alone
after school and with little else to do, they watch TV and they eat."
showed that girls who watched five or more hours of TV a day consumed
175 more calories daily than girls who watched one hour or less.