Think twice before eating that bagel with cream cheese and lox this Sunday at brunch—it would account for more than half of the daily “energy imbalance” cited as a reason for child obesity in a new Harvard School of Public Health (HSPH) report.

The study, led by HSPH researcher Y. Claire Wang, is the first to quantify the “energy gap”—the discrepancy between energy taken in and energy expended—specifically for youth.

“This is the first study of its kind to look at the population [of youth] as a whole, as well as those kids who became overweight teenagers today, and provide a concrete number to characterize the obesity epidemic that is being talked about a lot in the media,” Wang said.

The results reveal that, overall, children and teens consume between 110 and 165 excess calories on average per day, while overweight and obese youth have a caloric intake between 700 and 1000 calories more than necessary each day.

These additional calories, coupled with inadequate amounts of exercise, lead to an average of an extra 10 pounds of body weight for all youth and 58 pounds for those who are overweight.

Research that assessed this same discrepancy in adults identified an energy imbalance of only 30 calories, leading researchers to believe that small dietary changes would be enough to combat the obesity epidemic, according to HSPH researcher and Professor of the Practice of Health Sociology Steven L. Gortmaker.

However, the number of excess calories consumed by children indicate that bigger lifestyle changes are in order, Gortmaker said.

“The average energy gap is much larger than what other scientists have been projecting,” Gortmaker said. “The changes have to be more substantial.”

While the study focused on children and adolescents, it still carries important implications for college students.

“Overall, students aren’t as active as they should be here at Harvard,” said Community Health Initiative Co-Director Joseph K. Lee ’07. “Fitness and exercise have huge implications on physical and mental well-being.”