Summer 2012

Fat but Fit

Even if kids carry extra pounds, fitness has lasting health benefits

By Julie Flaherty

Being overweight doesn’t necessarily mean that you can’t shoot hoops and run bases like the rest of them. For overweight or obese children, it seems being or becoming fit may even lead to a healthier weight as they grow.

For a study published in the journal Obesity, Friedman School Assistant Professor Jennifer M. Sacheck, N01, and colleagues examined the association between weight and fitness levels in first through seventh graders attending school in Cambridge, Mass. They collected data on 2,793 students over four years. Regardless of their weight, students were classified as “fit” if they passed five different fitness tests, such as a 20-yard shuttle run.

“Obese and overweight girls who achieved fitness were almost five times as likely, and obese and overweight boys were two and a half times as likely, to reach a healthy weight than those who stayed underfit,” says first author Adela Hruby, N10, a Ph.D. candidate at the Friedman School.

It turns out that maintaining fitness is beneficial, too. “We observed that obese and overweight girls and boys who started and ended the study being fit were more likely to have a healthy weight by the end of the study,” she says.

illustration of kids running

Illustration: Marc Rosenthal

Staying fit also benefited the healthy-weight boys and girls; they were more likely to maintain their weight than those students who declined from fit to underfit over the course of the study.

The assessments coincided with a city-wide weight and fitness initiative that prompted improvements to gymnasiums, promotion of physical activities outside of school and issuing “Health and Fitness report cards” to parents.

Of the 1,069 students who were initially obese or overweight, 17 percent achieved a healthy weight within the study period. That compares with 6 percent of students who began the study at a healthy weight and became obese or overweight.

“It is encouraging to see any kind of reversal in unhealthy weight patterns,” Sacheck says, “considering Centers for Disease Control statistics indicate child and adolescent obesity rates rose approximately 13 percent between 1980 and 2008.

Julie Flaherty can be reached at

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