Is it time you blamed obesity for poor results?

By Amanda Gardner

Obese children and teenagers face a slew of potential health problems as they get older, including an increased risk of diabetes, heart attacks and certain cancers. As if that weren’t enough, obesity may harm young people’s long-term college and career prospects, too.

In recent years, research has suggested that obesity is associated with poorer academic performance beginning as early as kindergarten. Studies have variously found that obese students – and especially girls – tend to have lower test scores than their slimmer peers, are more likely to repeat classes and are less likely to go on to college.

The latest such study in the US, published last week in the journal Child Development, followed 6,250 children from kindergarten through fifth grade and found that those who were obese throughout that period scored lower on math tests than non-obese children.

What’s more, this pattern held even after the researchers took into account extenuating factors that can influence both body size and test scores, such as family income, race, the mother’s education level and job status and both parents’ expectations for the child’s performance in school.

Maths results

“In boys and girls alike who entered kindergarten with weight problems, we saw these differences in math performances emerge at first grade, and the poor performance persisted through fifth grade,” says lead researcher Sara Gable, an associate professor of nutrition and exercise physiology at the University of Missouri-Columbia.

The relations

However, Rebecca London, a senior researcher at Stanford University’s Gardner Centre for Youth and Their Communities, in Stanford, California and other childhood obesity experts caution that this emerging link is much more complicated than it seems. No one knows for certain why obesity and school performance are related, or whether one directly causes the other.

As London puts it, “Is it the actual state of obesity – those extra pounds – that are somehow influencing students’ achievement, or is it something related to the obesity but not the actual pounds?”

Social and emotional problems may not be the whole story, however. It’s also possible that some of the well-documented health problems associated with childhood obesity – such as asthma, diabetes, and sleep disorders – may interfere with schoolwork or cause kids to miss class time, Gable says.

Even more insidiously, excess weight or physical inactivity might sap a child’s brainpower at the cellular level, by causing inflammation and other harmful biological processes, says Robert Siegel, director of the Centre for Better Health and Nutrition, a pediatric obesity clinic at Cincinnati Children’s Hospital.

“Obesity affects virtually every organ system in the body, including the brain,” he says.