A new study, published in The Journal of Public Health which examined changes in BMI (body mass index) in children aged 4-11 years, found that that the number of obese children approximately doubles between the first and last years of primary school and that children who are obese when they start school are likely to continue to be overweight by the time they leave for secondary school.
This is the first study to use data from the same group of children as part of the Government's National Child Measurement Programme (NCMP).
The NCMP is an annual programme that involves the weighing and measuring of children in Reception year and Year 6 children in primary schools. It recognized internationally as a world-class source of public health intelligence and is used to monitor trends in bodyweight across England.
The study which was led by Matthew Pearce and colleagues analysed data from 1,863 children in South Gloucestershire whose weight was measured in 2006-7 when they were in reception and again in 2012-13 during their final year at primary school.
Matthew Pearce said: "Childhood obesity can lead to the development of significant health problems, lower physical fitness, lower self-esteem and a lower quality of life. In addition we know that obesity in childhood often leads to obesity in adulthood with all its related health issues.
"Our findings show that children who are overweight or obese in reception are unlikely to 'grow out' of excess weight - 84 per cent of obese or overweight children at Reception year went on to be either overweight or obese by Year 6.
"The results of this study should be a major concern for policymakers, as the increase in prevalence of obesity among primary school children occurred during a period of significant investment by the Government aimed at promoting healthy lifestyles. This investment involved the creation of a National Healthy Schools Programme to support children and young people to develop healthy behaviours using a whole-school approach.
"Previous research has shown that weight status tracks from childhood to adulthood; therefore, many of the overweight and obese children in our sample will become obese adults, and this will have a significant impact on their future health. Our findings suggest that parents and health professionals should be more vigilant in recognizing children at risk of becoming obese. It is therefore important that there is a greater focus on prevention for children who are likely to be on the path to obesity. Raising the potential risks with parents in terms of healthy growth is crucial to prevent future health problems, particularly as evidence suggests many parents and health professionals underestimate obesity in children and its importance.
"Reassuringly, our study does show that a small number of children did manage to reduce body weight. As far as we are aware ours is the first study to show that girls are more likely to successfully reduce their body weight to a healthy level compared to boys.
"It is important that further research is undertaken to identify what it was that helped them achieve this change - was it an in intervention by the school or their parents, or a change in lifestyle or parenting style? We recommend that further research is undertaken to explore what strategies led these children to achieve a positive shift in weight status."
The study found that of those children who were obese at Reception age, 68 per cent remained obese, 16.3 per cent had become overweight and 15.7 per cent achieved a healthy weight by Year 6. Of those children who were overweight at Reception, 27 per cent remained overweight, 30.3 per cent had become obese and 42.7 per cent achieved a healthy weight by Year 6. Of those children who were a healthy weight at Reception, 78.4 per cent remained so, 11.7 per cent had become overweight and 8.8 per cent became obese by Year 6.
Full details can be found in the Journal of Public Health article at: http://jpubhealth.oxfordjournals.org/content/early/2015/05/05/pubmed.fdv058.full?keytype=ref%2520&ijkey=D3RQOadtFW1bCwK
Current data NCMP data for 2013/14 show that the prevalence of obesity in South Gloucestershire is 7.1 per cent for Reception Children and 14.7 per cent for Year 6. This is below the national average of 9.5 per cent for Reception and 19.1 per cent of Year 6. Data for South Gloucestershire is also below the South West average which is 9.2 per cent for Reception and 16.7 per cent for Year 6.