Obese children face risks to their emotional and social well-being that can harm their academic performance, new research suggests.
The study, published today in the journal Child Development, found obese elementary school children performed worse on math tests than their peers without weight problems.
A lack of social acceptance could account for the lower test scores, researchers said. Obese children who do not feel accepted by their peers often exhibit feelings of loneliness, sadness and anxiety that can hinder their academic performance.
Those feelings became even more apparent as the children progressed through school, according to the study.
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“Children who have weight problems are not as well-received by their peers. That creates a condition or situation where developing social skills isn’t as easy," said Sara Gable, the study's lead author and an associate professor in the department of nutrition and exercise physiology at the University of Missouri, Columbia.
For girls, but not for boys, difficulty developing social skills was related to obesity.
“The stigma of obesity and lack of conformity to standards of physical appearance – girls are perhaps ... no pun intended, feeling the weight of that more,” Gable said.
The prevalence of childhood obesity in the United States has increased dramatically in recent decades. In the early 1970s, 5 percent of children ages 2 to 19 were obese. In 2007-08, 17 percent of kids in that age group were obese.
In California, physical fitness tests of public school students found 38 percent of children were overweight or obese in 2010. That rate varied dramatically across the state, from 11.3 percent among children in Manhattan Beach to 53 percent in Huntington Park.
For their study, the researchers analyzed data tracking 6,250 children nationwide from kindergarten through fifth grade. They compared the academic performance of students who were obese in kindergarten or first grade and remained so through fifth grade with children who were never obese. The data also included teacher reports of children's interpersonal skills and feelings such as sadness or loneliness.
When children were tested one-on-one in math, those who were obese began scoring lower than their peers in first grade, the study found. The timing suggests that the relationship between obesity and poor academic performance takes root as children progress in school, Gable said.
“Kids who start school with weight problems come to kind of understand that, you know what? Maybe other people don’t like me because of this,” she said. “I don’t believe these children are ‘less smart,’ but I do believe if they’re put into a situation where they’re being expected to perform ... they don’t perform as well.”
The study's findings persisted across demographic differences, including race, household income, maternal educational attainment and employment status, and parental expectations for their child’s educational achievement.
Teachers of boys and girls who were persistently obese reported that the children expressed more anxiety and sadness – feelings that, while not clinical diagnoses, may reflect students' struggles, Gable said.
In school, those feelings and poor social skills could mean that students are less engaged in learning or find classroom situations such as writing on the board in front of their peers “very anxiety producing,” she said.
Even though the study could not account for potential bias among teachers, their observations of obese boys and girls were consistent across grades and schools, Gable said.
Other factors related to obesity – such as health conditions that interfere with learning or school attendance – could affect academic performance as well and merit further study, she added.