Blog: Obesity in UK policing - is it a problem?

Published 16 Aug 2023
Written by
Professor John Harrison
National Police Chief Medical Officer
Reading time
7 mins

This blog has been written by Prof John Harrison the National Police Chief Medical Officer following the recent update sent to forces from the College of Policing on how to use BMI assessments during police officer recruitment.

"A quarter of Britain’s soldiers are classed as 'dangerously' overweight in the past five years, with more than 5000 discharged for being overweight or obese, since 2010” screams the  Mail on Sunday.

A former 'army chief' is quoted as saying “I believe that young overweight soldiers should be monitored very closely and if their weight cannot be controlled, they should be discharged.” There is a concern that dietary behaviour does not change in line with changes in duties and lifestyle. The current situation has been described as a failure of leadership by 'top brass'.

What does this mean for UK policing?

As an emergency service, there are standards of fitness to ensure that officers are deployable to the front line. The job-related fitness test, a core component of assessing fitness of recruits, as well as monitoring on-going fitness for personal safety training, is used to measure cardio-respiratory fitness. However, following recruitment, obesity measurement data is not routinely collected for police officer populations. Whereas MOD statistics can be interrogated to provide intelligence on the prevalence of obesity, type 2 diabetes and high blood pressure, we are largely ignorant about these important measure in UK policing at a national level.

There is evidence that metabolic syndrome is prevalent in law enforcement and appears to be increasing. A study in the US following the 2001 World Trade Centre (WTC) attacks found that approximately 25% law enforcement officers who worked at the WTC site met the criteria for metabolic syndrome.

Another prospective study of Chinese police officers concluded that work stresses are a risk factor for the development of metabolic syndrome. The National Police Wellbeing Service will be exploring how to address this issue through developing health assessments utilising the OK vans and the establishment of a police health observatory.

Entry standards for both the armed forces and the police have included measures of height and weight as surrogates for operational fitness. Body Mass Index (BMI) is a practical measurement that has been shown to correlate well with outcomes of obesity, such as high blood pressure and insulin-mediated glucose uptake. However, the military have found that use of BMI to assess obesity may be problematic because an increase in BMI might relate to an increase in the fat-free mass (largely muscle) but not fat mass. A specificity of about 0.96 means that some people with a high BMI are misclassified as obese, although the number of false positives will be small. In addition, BMI has a sensitivity of approximately 0.5 meaning that it does not detect almost half of people with high body fat levels.

Measurement of waist circumference is another option and the military have moved to a new approach to assessing obesity – body composition measurement, which combines BMI and waist circumference measurements. The risk of obesity in the UK armed forces has been shown to rise with age and in the lower ranks, for both men and women. The risk of obesity in officers an d the Royal Marines was less than for other study participants when a threshold of 27.5 Kg/m2 for BMI and waist circumference of 94 cm. (men) and 84 cm. (women) was used. The explanation was that the muscle mass was greater in these groups.

Despite entry thresholds for height and weight, a recent FOI request revealed that, between January 1 2019 and March 31 2022, 59,219 UK armed forces personnel had a recorded body composition measurement of increased risk of ill health (overweight). Medical discharges for the year 2022/23 reveal that the principal causes were musculoskeletal and mental health, which was in line with previous years.

In the absence of other information, obesity does not appear to be a direct cause of medical discharges. Secondary disability due to obesity is a possible reason for a musculoskeletal medical discharge. It might be the case that the other health conditions have contributed to the prevalence of overweight personnel? It is unclear as to the data source for the 5000 discharges due to being overweight or obese.

Given the current data, what is the purpose of the entrance standards?

If an applicant has no other health problems and is capable of passing the physical fitness and ability tests, why should s/he be denied entrance? Any health issues related to an elevated BMI, excessive waist measurement or other anthropomorphic test, is likely to develop later in life, after most military or police personnel have left the service.

A study in the Lancet found that, compared to a healthy baseline population, increased risks of all-cause mortality increased with BMI such that a BMI of 30 – 34.9 kgm2 increased the risk by 45% and a BMI of 35 – 39.9 kgm2 increased the risk by 94%. These are hazard ratios meaning that an increase of 94% is an almost doubling of risk. Is that sufficient to reject an applicant?

Similarly, using QRisk an otherwise healthy 25-year old male with a BMI of 35 – 40 kgm2 has a risk of having a heart attack or stroke over the next 10 years of 0.2%. Is that sufficient to reject an applicant? Does having a high BMI affect aerobic capacity? A study in the US, where Cooper tests (push ups, sit ups, sit and reach test and a 2.4 Km run) were introduced to assess physical fitness, found that, whilst a 1% incremental increase in body fat was associated with a decrease in performance, it did not impair candidates from meeting the threshold for fitness. The current UK police job-related fitness test (bleep test) is less demanding than the Cooper tests.

Evidence suggests, therefore, that the use of the BMI as a criterion of fitness for police officer applicants, on its own, is inappropriate. A pre-placement health assessment should address the relevance of current or previous health conditions and their relevance to the ability to perform the functional requirements of the job.

It is also important not to discriminate unfairly against applicants. Whilst under current legislation employees are not protected from discrimination on the grounds of obesity alone, there is now case law that has determined that being severely overweight, that is with a BMI more than 30 kgm2, can be a disability, if it affects ability to work. Long-term disability caused by obesity, such as impaired mobility, should be protected by disability laws.


In conclusion, there is clear evidence that obesity in the armed forces is increasing, and it now affects about 13% population. Questions have been posed about effective leadership and a commitment to the health and wellbeing strategy for the UK armed forces. Similar workforce data for UK policing is lacking. However, it seems likely that obesity may also be a problem that should be addressed. This should not be conflated with the performance of entrance measurements of obesity, which should only relate to the ability to perform the role of a police constable.

New guidance on medical standards for UK policing will be published in 2024. They will update existing Home Office standards from 2004. In advance of this, guidance has been shared with practitioners working in policing on the use of BMI in recruitment.