Boston (SmartAboutHealth) - Consuming too many calories maybe the reason for the obesity epidemic in America says the researcher of a new study.

The study found that on average, compared to 30 years ago, children weigh 9 pounds more than they used too, and adults weigh more than 16 pounds more than those living back in the 70’s.

According to researcher Australian professor Boyd Swinburn numbers indicate that the amount of physical activity has not dropped when it comes to Americans, but what they are eating has definitely changed for the worse.

What this means, is that Americans are consuming far more calories than they used too, and are not taking the time to work them off via exercise.

“Weight gain in the American population seems to be virtually all explained by eating more calories,” said Boyd Swinburn, M.D., of Deakin University in Australia, lead author of the study. “It appears that changes in physical activity played a minimal role.”

For children and adults to return to the weight of their peers of yesterday, they would need to cut out of their diets, 300 calories and 500 calories daily, respectively.

The study was presented at the 17th European Congress on Obesity, held from May 6-9, 2009, in Amsterdam.