Older Obese Kids Eat Less Than Normal-Weight Peers
One size doesn't fit all when it comes to explaining the cause of childhood obesity, North Carolina researchers say. Here's why.
MONDAY, Sept. 10, 2012 — Never-ending reports on childhood obesity have conditioned the public to instantly conjure images of heavy teens, stuffing themselves with sodas, pizzas, and chips.
But that may not be true, according to a new study published in the journal Pediatrics. In reality, older overweight kids are actually eating less than their normal-weight peers.
Researcher Asheley Cockrell Skinner, PhD, and her team at the University of North Carolina analyzed the diets of 19,125 children, ages 1 through 17, using data from the National Health and Nutrition Examination Survey. After analyzing age, weight, and calorie intake, they discovered that younger children who are overweight or obese eat more per day than healthy-weight peers, but as they grow older, the pattern is reversed. Interestingly, almost all girls level out their calorie intake around 12 or 13, whereas boys continue to consume more and more calories throughout their teen years, as their bodies build more muscle mass, Skinner says.
"I expected younger overweight kids to eat more and for adolescent eating patterns to be more similar," Skinner says. "But based on the anecdotal evidence we see where overweight teens say they're not eating more than their peers, I wasn't necessarily surprised by the findings."
What Causes Childhood Obesity?
Even as they ate less than their peers, heavy kids might still be heavy because of the other side of the diet equation: physical activity. Overweight adolescents are typically much less active than their healthy-weight peers, Skinner says.
"We need to put an emphasis on activity time and try to counteract all that sedentary time in school," Skinner says. Because overweight children typically become that way at a young age, she says parents should allow their kids to stop eating when they are full at all ages — banishing the clean plate rule for good. (Another recent study, this one published in the Journal of Developmental & Behavioral Pediatrics, confirms this hypothesis, finding that pressuring children to eat increases their obesity risk.)
Still, it doesn't all come down to eating and exercising. "I think there are so many factors that go into the development of obesity," Skinner says, "It's very hard to tease out what specifically is happening with every kid." Numerous studies have linked factors such as familial stress and poverty to early obesity.
Once a child is overweight, it's difficult to reverse the trend.
"With studies that we've seen in adults — and there's been a lot less done in kids — we know that if somebody who is overweight loses weight, their body reacts as if they are in starvation mode," Skinner explains. "It's to the point that if you've been overweight and you lose the weight, you will always have to eat fewer calories than someone who was never overweight."