More Sleep, Less Childhood Obesity
Skimping on Sleep May Make Children More Likely to Become Overweight or Obese
Why the Findings?
The reviewed studies were observational, so it's not clear which came first: extra pounds or less sleep.
It's also not clear how sleep affects children's weight. But Wang notes several theories:
- More time awake means more time to eat.
- Less sleep at night makes for drowsier, less-active days (and fewer calories burned).
- Sleep shortfalls may affect certain hormones. "This may increase people's feelings of hunger and also affect their energy expenditure," Wang says.
The links between sleep and BMI were stronger for boys than girls. The reason for that isn't clear, Wang says.
What About Genes?
That doesn't mean that other factors -- including genes, diet, and exercise -- aren't important. Just yesterday, another team of researchers noted heredity's influence on childhood obesity.
"I think people should be aware of all the important potential risk factors," Wang says.
He points out that genes may only have their full effect when the conditions are right -- and in the case of obesity genes, that might mean being in a setting ripe with opportunities to overeat.
"It's a coin; which side do you want to pay more attention to?" Wang asks, putting genes on one side of the coin and environmental factors on the flip side.
"I think from a public health perspective, people should pay more attention to environmental and behavioral factors," Wang says. He notes that gene tests and gene therapy aren't yet available for obesity. And though you can't change your genes, behavior can bend.