As part of our work on the National Childhood Measurement Programme (NCMP), we’ve followed the anonymised records of more than 33,000 children from Reception to Year 6 in four local authorities.

This has given us excellent insight into how a child’s weight status changes by the time they leave primary school and, from this, we’ve produced our first NCMP Tracking Report.

The key findings of the report suggest that being overweight or obese in reception is strongly linked to being overweight or obese in Year 6, highlighting the importance of starting school with a healthy weight.

With unhealthy weight becoming more common in society, we are all accustomed to seeing heavier body shapes. Our visual perceptions are becoming less reliable, making it difficult to know what a healthy weight should look.

While some may doubt if a child’s weight is indicative of their weight later in life and regard so-called ‘puppy fat’ as a normal part of early childhood, our data suggests this is not the case.

The NCMP measures the height and weight of Reception (age 4–5 years) and Year 6 (age 10–11 years) children in all mainstream state schools across England.

It's our most accurate indicator of prevalence and trends in childhood obesity and enables us to monitor a child’s weight so that schools, local authorities and health professionals can offer support to help children maintain or achieve a healthy weight.

We know this helps to reduce the adverse emotional, behavioural and health effects of obesity during childhood, while reducing the risk of ill health and premature death in adult life.

What does this new data tell us that we didn’t know before?

Whilst the annual NCMP report provides an accurate snapshot of obesity levels across the country, this is the first time they’ve been used to examine how the weight status of individual children changes as they progress through primary school.

While not nationally representative, the finding of the tracking report can help us to understand how a child’s weight status changes during primary school and has important implications for how we can help parents and children stay healthy.

What did we find?

The four local authorities in the study had a higher proportion of children from deprived areas and black and Asian ethnic communities than the national average.

They were also able to provide the linked data, which not all local authorities are able to do until 2019.

The results show that a child’s weight status in Reception is strongly predictive of their weight status in Year 6. For children who were overweight in Reception, about a third remained overweight, another third became obese and about one in ten became severely obese by Year 6.

For those obese in Reception, over a third remained obese in Year 6 and about another third developed severe obesity. Where children were severely obese in Reception, most remained severely obese in Year 6.

Most children who were a healthy weight in Reception remained at a healthy weight by Year 6.

While all children are at risk of becoming or remaining obese during primary school, these risks may be greater in children from more deprived backgrounds and those from certain ethnic minority groups.

Encouragingly, the report shows that some children (around 27% overweight and 16% obese) with an unhealthy weight in Reception were able to achieve a healthy weight by Year 6.

This tells us that an unhealthy weight can be reversed. We're keen to learn more about the reasons and motivations for children returning to a healthy weight and we will look at this further.

What do the results mean and what resources can we use to act on them?

The results highlight the importance of helping children to have a healthy weight in early childhood. It also confirms that health inequalities are having a detrimental impact on some children, increasing their risk of developing serious and preventable long-term illnesses.

This new insight can be utilised by commissioners, providers of children’s services and everyone working with children and families. This includes early year services, schools, GPs and other health care professionals.

At PHE we understand the multi-faceted support required to help children return to a healthy weight.

This includes support to parents through Change4Life; helping to promote healthy eating and physical activity in children’s centres and nurseries; and via schools adopting a whole-school approach to integrate healthy lifestyles into their daily routine.

The ‘Our Healthy Year’ materials give ideas for schools to be healthy, while embedding the NCMP into school life.

They support action to create healthier communities, providing more opportunities for children to be healthy.

The Government’s Child Obesity Plan sets out an ambitious plan to reduce child obesity.

As part of this, PHE is working with the food, catering and hospitality sectors to make healthier options more accessible, which includes the reduction of sugar in everyday foods.

However this alone will not solve the problem and change must also come from within our homes, schools and communities.

Talking about a child’s weight can no longer be taboo – that is why the confidential NCMP letters to parents are an important step in sensitively advising that their child’s weight may be an issue.

Many local areas use this to signpost families to health professionals and support services.

Most of us would take action if a child were to take up smoking; we as a society must realise that excess weight in childhood is not only dangerous, but a treatable and avoidable condition affecting the future of our children.