That could be. I think the study is flawed but at the same time, it's important to be doing such studies. This is a real problem. I was recently at a museum and there was a school group coming through at the same time. I was shocked by how many of these 8-10 year olds were over weight. It was rare that a kid was obese when I was growing up, now it's commonplace.
If you think its bad now, wait 10 -15 years. All these fat kids will be adults by then (having even fatter children), and the diabetes problem we have now will look quaint by comparison. Heart disease, stroke and diabetes are going to be the major health challenge of the 21st c. No amount of health care can solve this problem. Its a societal issue that involves everything from instant gratification to parenting to the food system. We need a dramatic phase change, but how to get there is a mystery.