New research out of Canada and the United States suggests that overweight children are suffering from low self-esteem as early as kindergarten - and the psychological consequences continue to haunt them later on in life.
Published in the journal Applied Developmental Science, a University of Missouri study analyzed the social and behavioural development of 8,000 American children who entered kindergarten in 1998. Using data collected by the U.S. Department of Education's Early Childhood Longitudinal Study, which surveyed both teachers and children, the study's researchers followed the children's development until they reached Grade 3.
Using body mass index as a measure, researchers analyzed previously unstudied factors - such as the age of becoming overweight and the length of time children are overweight - and found that heavier kids began to show signs of sadness, loneliness and anxiety as young as 6.
Furthermore, as these children progressed from kindergarten to Grade 3, their negative feelings grew more pronounced, lead researcher Sara Gable says.
"They actually get worse, so you think about the mental health implications of that," says Dr. Gable, an associate professor of human development and family studies. "It just adds to the body of research that we already have telling us the cost of the lifestyle problems apparent in the U.S. population."
Overweight girls were especially affected by their heavy stature, Dr. Gable adds. Bigger girls had trouble getting along with their peers and exhibited other negative behaviours that emerged after kindergarten, including a lack of self control.
For girls who were overweight since kindergarten, these behaviours began manifesting in Grade 1. The same was also true for Grade 1 girls who were not defined as overweight but became so by Grade 3.
Dr. Gable says this finding is especially intriguing because it suggests that a general reliance upon BMI classifications is flawed. She says parents and doctors might tend to overlook weight gain in children until their BMI hits the 95th percentile, which is the widespread classification for childhood overweight or obesity.
"It's kind of sounding the alarms for the medical community in terms of the consequences [emerging]before the children cross that traditional threshold," she says. "This suggests to me that you don't want to wait until they're overweight … to start talking to parents and getting involved."
Meanwhile, a report published by Statistics Canada on June 17 found similar conclusions to Dr. Gable's study.
Focusing on the 10 to 11 age group, the report found that overweight children were twice as likely to report low self-esteem compared with kids of regular weight.
"Obese children are at increased risk of low self-esteem," the study concludes. "The downstream consequences may be important, given that other studies have shown low self-esteem to be associated with poor mental health later in life."
Both studies are troubling in light of the ballooning populations of obese children in North America. In Canada, childhood obesity has become a "pandemic," according to the Stats Canada report; in 2004, 26 per cent of children between ages 2 and 17 were considered overweight or obese, a 70 per cent increase from 1978/1979 levels.
In the United States, the rate of obesity for children aged 6 to 11 is now at 17 per cent, according to the most recent data from the National Health and Nutrition Examination Survey, conducted between 2003 to 2006. This is also a prominent increase; between 1976 and 1980, only 6.5 per cent of children aged 6 to 11 were considered obese.
Toronto-based child psychologist Jancy King warns that overweight children suffering from low-self esteem run the risk of developing future problems, such as eating disorders, people-pleasing tendencies and unhealthy sexual behaviour as adults, to name a few.
"Kids will learn very, very quickly that they're not meeting the criteria," she says. "And once you run into low self esteem it's pretty much for life until you get some treatment."