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The prevalence of primary school children living with obesity continued to fall in 2022/23, after reaching highest recorded levels during the Covid-19 pandemic, new NHS England figures show. However, obesity prevalence among year 6 children, aged 10 to 11, remains above pre-pandemic levels.

Notes for editors

1. The obesity prevalence includes severe obesity.  

2. Each year, children in reception and year 6 are measured. This means that a separate set of children are measured each year and there is no follow up of specific cohorts (other than the six years of elapsed time when reception children become year 6 children). For example, the children measured in 2022/23 were different children from those measured in 2021/22.    

3. The Covid-19 pandemic affected how much NCMP data was collected and this is described in more detail in the report. The NCMP usually measures the height and weight of over one million children in England annually. In 2020/21, due to the coronavirus (COVID-19) pandemic disrupting the collection, a sample of 300,000 children were measured. Statistical weighting was applied to the data to ensure the sample is reflective of the population measured by NCMP in England in previous years and comparable. Details of this are in the Methodology and Data Quality section of the 2020/21publication. The 2019/20 NCMP collection was incomplete because no measurements were taken after March 2020, when schools were closed as part of the response to the COVID-19 pandemic. Data quality work on the 2019/20 data established that it is comparable to earlier years at the England level. The 2018/19 school year was the last complete collection of NCMP data that was unaffected by COVID-19. 

4. The National Child Measurement Programme (NCMP) now holds 17 years of data, from 2006/07 to 2022/23.     

5. The NCMP is a key element of the Government’s approach to tackling child obesity by annually measuring over one million children and providing reliable data on the prevalence of children living with obesity. Children are measured in reception (aged 4–5 years) and year 6 (aged 10–11 years) in mainstream state-maintained schools in England. Independent and special schools are excluded from the analyses in this publication. NHS England collect NCMP data each year and produce the first annual statistical publication. After this, OHID conduct additional analyses of NCMP data and website links to their publications are provided in Part 7: Other data sources in this report.  

6. The BMI classification of each child is derived by calculating the child’s BMI centile from the British 1990 growth reference (UK90). This approach is recommended by The National Institute for Health and Care Excellence (NICE). The classification is as follows:   

   • BMI centile <=2: Underweight   
   • BMI centile >2 and <85: Healthy weight   
   • BMI centile >=85 and <95: Overweight   
   • BMI centile >=95: Obesity   
   • BMI centile >=99.6: Severe obesity (Note: “Severe obesity” is a subset of “Obesity”. Children with a BMI centile of between 95 and 100 are classified as “Living with obesity” and those with a BMI centile of between 99.6 and 100 are classified as “Living with severe obesity”).    

7. Data is collected primarily in mainstream state-maintained schools in England. Any data collected from independent or special schools is excluded from this analysis. Local Authorities measure children during the school year with the programme running between September and August each year to coincide with the academic year.   

8. Comparisons between groups and over time have been statistically tested to determine whether differences are likely to be genuine (i.e., statistically significant) or the result of random natural variation. Only statistically significant differences have been described with terms such as ’higher’, ’lower’, ’increase’ or ’decrease’. When a comparison does not show a statistically significant difference, this is described using terms such as ‘similar to’ or ’the same as’.    

9. Geographical analyses in this report are primarily based on the postcode of the child’s home address. Some time series analyses use the school postcode as the child postcode was poorly populated in the early years of the NCMP and these are labelled in the report

10. Local authority data reported here is by the upper tier local authority where the child lives. Data is also provided in the report for lower tier local authorities.