How Your Child's Weight Affects School Readiness


The authors of this study analyzed and compared how students who are healthy weight, underweight, overweight and obese performed on a set of measures at the start of school.

Five Domains of Development

To conduct their analysis, the researchers relied on data from the Australian Early Development Census (AEDC), colloquially referred to as “the census of child development.” They chose this survey because it collects information on 5 key areas of early childhood growth. Specifically, it measures “physical health and wellbeing, social competence, emotional maturity, language and cognitive skills, and communication skills and general knowledge.”

This study was based on students approximately five years old, who participated in the census in 2009 shortly after they started school. Prior to the AEDC survey, all of the students had a “health check,” which included typical measurements, like height and weight.

The AEDC classifies students based on their performance across all five domains. The authors explain that “children with scores below the 10th percentile on each domain are categorized as being developmentally vulnerable.”

The researchers took the students’ height and weight to calculate their BMI’s and then examined how underweight, healthy weight, overweight and obese BMI’s related to the frequency of the “vulnerable” label in the various AEDC spheres.


In terms of vulnerability across AEDC measures, the researchers did not find any observable differences between underweight and healthy-weight children. When comparing overweight and healthy-weight children, the differences were insignificant except in the language and cognitive skills domain where there were fewer vulnerable children in the overweight group than in all other groups. The authors conclude that being overweight may have “possibly protective effects” in this sphere of development.

The obese group fared the worst across all measures. This group had the highest number of students vulnerable in social competence, emotional maturity, language and cognitive skills, and communication and general knowledge, with noticeable increases compared to the other weight groups. The obese children also had a drastically higher percentage of students vulnerable in the physical health and wellbeing area. The authors stated that “obese children were around 30% more likely to be vulnerable on the social competence domain, which refers to overall social competence, responsibility and respect, approaches to learning, and readiness to explore new things.”


As the authors assert, and we would all agree, “every child has the right to healthy development.” However, as the study illuminates, this right is obstructed for many obese children. Their higher vulnerability in physical health affects their school experience and ability to grow in many concrete ways. Implications of this vulnerability include obstacles related to fine motor, gross motor, and physical independence.


The authors conclude that the focus on obesity prevention must begin before students even start school, as their sample arrived at the start of their education with the deck already stacked against them. The researchers also caution that focus shouldn’t be limited to obese children, but should also include those who are overweight, to ensure that the latter group doesn’t advance into obesity, a category that showed much more risk for developmental issues.

StepUp Summary:

At StepUp we believe that in early childhood, the strongest emphasis should be placed on physical activity that promotes both cognitive and motor development. Our programs are centered around helping children improve their coordination of cognitive and motor skills in an educational environment that encourages self-evaluation and trial and error problem solving. 

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