ORLANDO -- Three-year-olds pack away 46 calories, mostly in sugar-laden snacks and drinks, for every hour they spend watching television, researchers here reported. This can add up.
ORLANDO, March 2 -- Three-year-olds pack away 46 calories, mostly in sugar-laden snacks and drinks, for every hour they spend watching television, researchers here reported. This can add up.
Typically toddlers watching television -- either TV programs or videos -- are consuming extra servings of fruit juice or cookies and at the same time consuming less healthy foods such as vegetables and fresh fruit, and said Sonia Miller, a Harvard Medical School student.
Miller reported results of Project Viva, a childhood nutrition study, at the Conference on Cardiovascular Disease Epidemiology and Prevention, which is sponsored by the American Heart Association.
And that, according to findings culled from Project Viva, a nutrition study of more than 1,200 toddlers funded by the National Institutes of Health, may be just the beginning of a habit that could add contribute to obesity by the time they reach middle school, said Matthew Gillman, M.D., S.M., of Harvard, the senior author.
Dr. Gillman said that published studies have concluded that much of the increase in adolescent weight over the past decade could be explained by the consumption of an additional 150 calories a day.
The excess calories consumed by TV watching toddlers, "represented about a third of the increase calorie intake observed in adolescents," he said.
Calorie intake and TV-viewing time was assessed by questionnaires administered to mothers of 1,203 children who were enrolled at birth in Project Viva, a study of childhood nutrition in Massachusetts funded by the National Institutes of Health.
Eighty-seven percent of the children came from families with household incomes of more than ,000 a year and 72% of the mothers had at least a college degree.
After controlling for potential confounders including parental body mass index "we found that for every hour of viewing time, total calories consumed increased by 46.3 kcal/day," Miller said.
Additionally, each one hour of TV or video viewing was associated with an increase of 0.06 in servings of red or processed meats per day, one more serving of juice per week, as well as an additional 0.3 serving of fast food per month, and a 0.05% increase in daily consumption of energy from trans fats, Miller said.
Moreover, this increase was observed even though as a group the children had TV viewing habits that were well within the recommendations of the American Academy Pediatrics, which recommends no TV viewing before age two and no more that two hours a day after age two.
"The average viewing time in our study was just 1.7 hours," Miller said.
But "there was no threshold effect, no amount of TV time which did not add calories," Dr. Gillman said.
At the same time, every hour of TV or video viewing was associated with decreased servings of fruits and vegetables (-0.2 servings/day), a 23.2 mg decrease in daily calcium consumption and a decrease in dietary fiber (-0.4 g), she said.
There was no indication about whether the data were significant.
Dr. Gillman conceded TV watching and physical activity are not mutually exclusive, a number of studies have suggested that as viewing time increases physical activity decreases.
Likewise, Dr. Gillman said that the link between TV and snacking has been previously reported.