Obesity is a major public health problem, both internationally and within the UK. Being overweight or obese is associated with an increased risk of a number of common diseases and causes of premature death, including diabetes, cardiovascular disease and some cancers. The risk of poor health is strongly correlated with body mass index (BMI).
Evidence also suggests that obesity is associated with an increased risk of severe illness and death from the coronavirus (Covid-19). In July 2020, the government launched a campaign encouraging adults to lose weight and published Tackling obesity: empowering adults and children to live healthier lives, which outlined policies to support healthy eating and expand NHS weight management services.
Childhood obesity is associated with various health conditions, including asthma, early onset type 2 diabetes, and cardiovascular risk factors. Children who are obese are also more likely to suffer from mental health and behavioural problems. In addition, being an obese child can have long-term health consequences, as childhood obesity is a strong predictor of adult obesity.
In 2016, the government launched Childhood obesity: a plan for action, which set out a number of actions primarily focused on reducing sugar consumption and increasing physical activity among children. In June 2018, an update to the action plan was published, setting a national ambition to "halve childhood obesity and reduce the gap in obesity between children from the most and least deprived areas by 2030".
The Health Survey for England collects height and weight measurements from a representative sample of the general population, which are used to calculate body mass index (BMI) statistics. This measure allows us to estimate the proportion of the population who are overweight (BMI ≥25kg/m2 to <30kg/m2) or obese (≥30kg/m2).
This indicator shows trends in obesity and overweight in adults from 1993 to 2019. The prevalence of obesity increased sharply between 1993 and 2000, with a slower rate of increase after that. In 2019, 36% of the adult population were overweight and 28% were obese.
Comparing men and women in 2019, 29% of all adult women were obese and 31% were overweight, whereas 27% of adult men were obese and 41% were overweight (data not shown).
The National Child Measurement Programme (NCMP) collects the height and weight measurements of over one million children in Reception (aged 4-5 years) and Year 6 (aged 10-11 years) in mainstream state schools in England.
One in five children in Year 6 (aged 10-11 years) were obese in the 2019/20 school year (21%). This is more than double the proportion of children in Reception who were obese (9.9%). Data collection for the 2019/20 school year ended in March 2020 when schools closed as part of lockdown measures during the Covid-19 pandemic. However, analysis found that national results are directly comparable to earlier years. Obesity in children aged 10-11 increased by 3.6 percentage points between 2006/07 and 2019/20. The proportion of children who were overweight or underweight has remained relatively stable over this time period.
Overall, the proportion of children in Reception (aged 4-5 years) who were obese, overweight, a healthy weight, or underweight has remained relatively unchanged since 2006/07. In 2019/20, 13.1% of children aged 4-5 years were overweight and 9.9% were obese (data not shown).
There is a strong association between deprivation and obesity in children. In 2019/20, the prevalence of obesity in children aged 4-5 was almost twice as high in the most deprived areas (13%) compared to the least deprived areas (6.7%). The government’s Childhood obesity: a plan for action: Chapter 2 has set a national ambition to significantly reduce the gap in obesity between children from the most and least deprived areas by 2030. Between 2006/07 and 2019/20, the gap in obesity prevalence for children aged 4-5 increased from 4.5 to 6.5 percentage points.
In 2019/20, the prevalence of obesity in children aged 10-11 was 27% in the most deprived areas and 14% in the least deprived areas. Between 2006/07 and 2019/20, the prevalence of obesity has remained roughly constant in the least deprived areas, but has increased steadily from 21% to 27% in the least deprived areas. As a result, the gap in obesity prevalence between children from the most and least deprived areas increased from 8.5 percentage points to 13.3 percentage points over the same time period.
About this data
This indicator story presents findings on the prevalence of overweight and obesity for adults from the Health Survey for England and for children from the National Child Measurement Programme.
The Health Survey for England (HSE) consists of an interview at which height and weight are measured. This enables the calculation of body mass index (BMI), which is defined as weight in kilograms divided by the height in metres squared (kg/m2), a measurement which is used to define overweight or obesity. Adults were classified into the following BMI groups according to the World Health Organisation (WHO) BMI classification:
- Underweight – less than 18.5kg/m2
- Normal – 18.5 to less than 25kg/m2
- Overweight, not obese – 25 to less than 30kg/m2
- Obese, including morbidly obese - 30kg/m2 or more
- Morbidly obese – 40kg/m2 or more
The National Child Measurement Programme (NCMP) was introduced in 2006/07 and collects height and weight measurements for children in Reception (aged 4-5 years) and Year 6 (aged 10-11 years) in mainstream state schools in England. The programme now holds 13 years of data and annually measures over one million children. The national participation rate increased from 80% in 2006/07 to 95% in 2018/19. In the 2019/20 school year, data collection finished early when schools closed in March 2020 due to the Covid-19 pandemic. Data quality analysis carried out indicated that figures from 2019/20 are directly comparable to previous years. For more information, see the National Child Measurement Programme – England, 2019/20: Data Quality Statement. The HSE also collects data on childhood obesity, however as it is a sample the estimates are less precise than those for NCMP.
The BMI classification of each child is derived by calculating the child's BMI centile and classifying according to age and sex to take into account different growth patterns in boys and girls. The NCMP uses the British 1990 growth reference (UK90) to define BMI classifications. Deprivation is defined by the deprivation decile of the lower super output area of the school the child attends.
It is likely that Year 6 obesity prevalence in the first years of the NCMP (2006/07 to 2008/09) were underestimates due to low participation. This, and the impact of other improvements in data quality, should be considered when making comparisons over time. For further information, see the National Child Measurement Programme - England, 2019/20: Appendices.