Watching too much TV may make children fat, bad at math and expose them to all kinds of other evils, say "child experts" writing in the Archives of Pediatrics and Adolescent Medicine. The authors found that television exposure at age two forecasts negative consequences for kids, ranging from poor school adjustment to unhealthy habits.

Since TV exposure encourages a sedentary lifestyle, television viewing must be curbed for toddlers to avoid the maintenance of passive mental and physical habits in later childhood, the researchers conclude.

"We found every additional hour of TV exposure among toddlers corresponded to a future decrease in classroom engagement and success at math, increased victimization by classmates, have a more sedentary lifestyle, higher consumption of junk food and, ultimately, higher body mass index," says lead author Dr. Linda S. Pagani, a psychosocial professor at the Université de Montréal.

1,314 kids took part in the investigation, which was part of the Quebec Longitudinal Study of Child Development Main Exposure. Parents were asked to report how much TV their kids watched at 29 months and at 53 months in age. Teachers were asked to evaluate academic, psychosocial and health habits, while body mass index (BMI) was measured at 10 years old.

According to the investigation, watching too much TV as toddlers predicted a seven percent decrease in classroom engagement; a six percent decrease in math achievement; a 10 percent increase in victimization by classmates; a 13 percent decrease in weekend physical activity; a nine percent decrease in general physical activity; a 10 percent peak in snacks intake; and a five percent increase in BMI.

"Although we expected the impact of early TV viewing to disappear after seven and a half years of childhood, the fact that negative outcomes remained is quite daunting," says Dr. Pagani. "Our findings make a compelling public health argument against excessive TV viewing in early childhood and for parents to heed guidelines on TV exposure from the American Academy of Pediatrics."

 "Common sense would have it that TV exposure replaces time that could be spent engaging in other developmentally enriching activities and tasks which foster cognitive, behavioral, and motor development," Pagani says.

Citation: Linda S. Pagani, Caroline Fitzpatrick, Tracie A. Barnett, Eric Dubow, 'Prospective Associations Between Early Childhood Television Exposure and Academic, Psychosocial, and Physical Well-being by Middle Childhood', Arch Pediatr Adolesc Med, May 2010, 164: 425 - 431