Obesity

We look at how the proportion of the population who are overweight and obese has changed over time.

Qualitywatch

Indicator

Last updated: 20/10/2023

Background

Obesity is a major public health problem, both internationally and within the UK. Being overweight or obese is associated with an increased risk of several common diseases including diabetes, cardiovascular disease and some cancers. Evidence also suggests that obesity is associated with an increased risk of severe illness and death from Covid-19.  

In July 2020, the government published Tackling obesity: empowering adults and children to live healthier lives, which outlined policies to support healthy eating and expand NHS weight management services. In September 2022, the government released a plan on the non-promotion of food and drinks high in fat, salt, or sugar by restricting volume offers like ‘buy one get one free’. However, the implementation of this plan has been delayed until October 2025.

Childhood obesity is similarly a major public health problem. Children who have obesity are at greater risk of high blood pressure, high cholesterol, diabetes and other long-term conditions that last into adulthood. 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 2021. The prevalence of obesity increased sharply between 1993 and 2001, followed by a slower rate of increase in the following years. In 2021, 38% of the adult population were overweight and 26% were obese. The proportion of adults who were underweight is not reported for 2021 because certain methodological factors make those estimates unlikely to be accurate. See ‘About this data’ for more information.

Comparing men and women in 2021, 26% of all adult women were obese and 32% were overweight, whereas 25% of adult men were obese and 43% were overweight (data on differences in gender not shown). Due to the Covid-19 pandemic, data was not collected in 2020 and no publication was released.


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.

Between 2006/07 and 2019/20, the prevalence of obesity had increased from 17.5% to 21%. In 2020/21 there was a sizeable increase in the prevalence of obesity in children. One in four children (26%) in Year 6 were obese or severely obese in the 2020/21 school year, up from one in five in 2019/20 (21%). One in seven children (14%) in Reception were obese or severely obese in the 2020/21 school year, up from one in 10 in 2019/20 (10%) (data not shown). In 2021/22, the prevalence of obesity in children decreased but remained higher than the estimate in the pre-pandemic period. For Year 6 children, the prevalence decreased to 23%, and for children in Reception it returned to 10%.

Between 2006/07 and 2021/22, the proportion of children with a “healthy weight” decreased by 6 percentage points for those in Year 6 while no significant change was recorded for those in Reception. The proportion of children who were overweight or underweight has remained relatively stable over this time period.

When looking at the prevalence of obesity by ethnicity for children in Year 6 in 2021/22, children described as “Chinese” (18%) had a lower rate of obesity compared to the average (23%). However, children described as being “Mixed”, “Asian” and “Black” had a higher rate of obesity than the average; 25%, 28% and 33% respectively.


There is a strong association between deprivation and obesity in children. This is in line with recently published evidence that states that obesity levels in children are likely to be higher in areas where low income families reside. In 2021/22, the prevalence of obesity in children in the most deprived areas was more than double the value in the least deprived areas. This is true both for children in Reception and in Year 6.

In 2020/21, the prevalence of obesity in children increased significantly. Between 2019/20 and 2020/21, the prevalence of obesity in Reception-aged children increased from 13% to 20% in the most deprived areas; in the least deprived areas this increased from 7% to 9%.  Similarly, the prevalence of obesity in children in Year 6 increased from 22% to 32% in the most deprived areas, and from 13% to 16% in the least deprived areas. The increase in prevalence was disproportionately higher for children in the most deprived areas.

In 2021/22, the prevalence of obesity returned closer to pre-pandemic levels particularly for Reception-aged children, while for Year 6 children the level of obesity remained higher than in 2019/20. The prevalence of obesity for Year 6 children from the most deprived areas was 3 percentage points higher in 2021/22 than in 2019/20, at 30% in 2021/22, double the prevalence recorded for similar-aged children from the least deprived areas (15%) in that year. In 2021/22, the prevalence of obesity in Reception-aged children in the most deprived areas was 13%, and 7% for Reception-aged children from the least deprived areas.

The government’s Childhood obesity: a plan for action: Chapter 2 had set a national ambition to significantly reduce the gap in obesity between children from the most and least deprived areas by 2030. However, between 2006/07 and 2021/22, the gap in obesity prevalence for children increased by 2.2 percentage points for 4–5-year-olds and 6.7 percentage points for 10–11-year-olds.

About this data

This indicator 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

HSE data up to and including 2002 is unweighted, and from 2003 onwards data has been weighted for non-response. For more information, please see the methods report and data quality statement. 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.

Due to the impact of the Covid-19 pandemic, the 2020/21 collection was carried out as a sample and statistical weighting was applied to the data to produce an estimate of obesity prevalence at national level. Data quality investigations determined that weighted 2020/21 data is representative of the population and results are broadly comparable with previous years. For further information, see the National Child Measurement Programme, Summary, 2020/21. 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 with 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.

Data in 2021 were calculated using adjustments to self-reported height and weight. These adjustments were calculated using associations derived from HSE 2011-2016. BMI status is presented only for three mutually exclusive groups (Not overweight nor obese: <25kg/m2; Overweight: ≥25 to <30kg/m2; Obese, including morbidly obese: ≥30kg/m2) in 2021 due to corrected data likely being less accurate at the low and high ends of the BMI scale.

The BMI classification of each child is derived by calculating the child's BMI centile and classifying according to age and sex to account for 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) was underestimated due to low participation. This, and the impact of other improvements in data quality, should be considered when making comparisons over time.

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