Monday, May 11, 2009
Why the food and exercise police are unsuccessful
The human body is an amazing thing. Amazing! As every dieter knows, if you cut back on its fuel one day, you'll feel hungrier the next as your body tries to compensate. Turns out the same model applies when it comes to physical activity. If you give kids more gym time, more time spent running around, they become less active when they're not in school.
At least, that what a new study done in the Netherlands shows. The study results, presented last week at the European Congress on Obesity, demonstrated yet again why trying to manipulate kids' eating habits and weight through "interventions" is ineffective. Researchers looked at kids from three schools, who got 9.2, 2.4, or 1.7 hours of scheduled phys ed time in a school week, and found that kids' activity levels averaged out to be exactly the same no matter how much gym they got in school. Those who didn't get much PE time at school became more active at home, while those who got a lot of PE in school did less at home.
"We believe the range of activity among children, from the slothful to the hyperactive, reflects not the range in environmental opportunities, but the range of individual activity set-points in the brains of children," said Alissa Frémaux, a biostatistician (I didn't even know there was such a thing! very cool) who analyzed the study.
I think more PE time in schools is a great thing, especially when there are big gaps in the socioeconomic status of kids. While some kids get carted around to ballet and soccer, too many kids have no opportunities outside of school to move, be active, exercise, and have physical fun. So I'm all for piling it on at school.
Just don't expect more gym time to equal thinner children. And don't think that lowering the fat content of school lunches will translate into thinner kids, either.*
*I am deliberately leaving aside the notion of whether these are desirable outcomes. The plain truth is that they're not achievable. Constant readers know what I think anyway.
**Thanks, as usual, to Jane for pointing me toward this research.