From November 2004 to May 2006, researchers at the Harvard School of Public Health analyzed data from the Centers for Disease Control and Prevention (CDC) to estimate how changes in "energy balance"—i.e., the relation between energy intake and expenditure, expressed in calories—have contributed to increasing levels of obesity among children.
Researchers also examined how specific interventions targeting energy balance—including reducing the consumption of sugar-sweetened beverages and time spent watching television—could help halt the rise in overweight among children.
U.S. overweight teens ages 12 to 17 consumed an average of 700 to 1,000 calories more than required each day over a 10-year period, leaving them 58 pounds over their recommended weight, on average.
Compared with the "normal growth scenario"—in which weight gain occurs only in proportion to height gain—boys and girls ages 2 to 7 gained an excess of 0.95 pounds per year, on average, over the 10-year period.
Assuming that 3,500 unused calories leads to an average of one pound of weight gain, a reduction of 110–165 calories per day (or an equivalent increase in activity) could have prevented this increase.
Children should take longer and more frequent physical education classes that require them to be physically active for at least half of the class time.
Children should reduce the consumption of sugar-sweetened beverages in schools and at home.
Children should consume less fast food and decrease the time spent watching television.