On 18 March, the Times reported that NICE (National Institute for Health and Care Excellence) had opened a consultation on an updated version of their general guidance document in which it proposed that millions should have an annual weigh-in to fight obesity. These weigh-ins would take place at doctor’s surgeries and will be aimed at those who have certain conditions including diabetes, arthritis and heart failure. The consultation runs until 15 April 2025. [Ref 1, 2, 3]

The Royal College of GPs has however warned that since services are already over-stretched, any such campaign needs to be properly funded.

While it is not up to the UKMA to comment on the practicality or otherwise of the proposal, it is prudent to point out that in the long run, unless people’s weights are communicated in kilograms, the exercise is likely to run into problems.

The medical profession has been recording patients’ weights in metric units for a number of decades. In 2010 the Department of Health, following a review by the Local Authorities Coordinators of Regulatory Service (LACORS) issued the “Estates and Facilities Alert EFA/2010/001” in which it states all medical practitioners were required to use CE certified Class III or Class IIII weighing devices (as appropriate). It is mandatory that such devices be calibrated in metric units only with displays in imperial units prohibited. Prior to that some medical establishments had been using bathroom scales that had been purchased from high street outlets, and which did not undergo regular calibration. [Ref 4]

Patients have every right to be told their weights. There is no official guidance to medical practitioners as to what units they should use when communicating with their patients. As a result of the persistent use of imperial units in the press, many patients expect medical practitioners to communicate their weights to them in “old money” (aka imperial units). Some practitioners oblige but other suggest that the patient look up the conversion for themselves.

Once many readings have been taken, it might well be appropriate for the medical practitioner to comment on changes over time. While it might appear to the casual reader that conversion from kilograms into stones and pounds is a simple matter, there are hidden complications. How many people are conversant with equating “half a stone” with “7 pounds”? (On a live broadcast, Lord Parkinson showed that he was not able to do so.) Using the language that the patient understands also puts pressure on the practitioner as to whether to use stones and pounds or stones and fractions of a stone or, for those who prefer metric units, to use kilograms.

Another bugbear is printing out details of changes in a person’s weight over time. One of the classic ways of displaying data is using a graph. Many graphics packages have outputs that are designed to be incorporated into data handling packages. Most such packages are decimal based (apart from handling dates and times) and as a result such packages cannot produce decent graphs with stones and pounds on the y-axis. A cheap work-around might be to display stones and decimals of a stone but this would be a sign of shoddy design and would only serve to cloud the results further. The only real solution is to use a decimal-based system of units which, in the UK, means kilograms.

If His Majesty’s Government is minded to getting the most out of the exercise, it makes sense for them to encourage the use of kilograms by all sectors of the population. A YouGov survey taken in 2022 showed that 72% of the British population weigh themselves using stones and pounds with 24% using kilograms. The survey also showed marked variations across different socio-economic groups. The highest take-up of metric units was amongst the younger age groups with 44% of those in the 18-29 age group using metric units as opposed to 11% in the 70+ age group. There were also marked variations across the country’s regions with 40% of Londoners using kilograms as opposed to 28% of Scots and 18% of those who live in the Midlands or Wales. The use of kilograms was most prevalent amongst LibDem supporters (33%) as opposed to 14% amongst Conservatives while 27% of EU Remainers preferred metric units as opposed to 13% of Leavers. [Ref 5]

In South Africa (where I lived until 1978), the government took the lead in promoting metrication by, amongst other things, banning the sale of measuring devices that displayed imperial units (with or without metric equivalents). This approach might also have worked in the UK during the 1970’s, but in today’s political climate such an approach would not work. If the British Government is to get the most out of an anti-obesity program, it needs to take the lead in ensuring that medical practitioners and patients use the same units to communicate with their patients as they use amongst themselves and that language is unquestionably the metric system.

Although the general public has not been invited to partake in the NICE consultation, it would be appropriate if one of the outcomes of such a consultation is that a program be put in place to ensure that medical professionals and the general public all use the same system of units as each other. The UKMA as an organisation is of course neutral as to the practicality of annual weigh-ins.

References

1. The Times – March 18, 2025 – Millions will have annual weigh-in to fight obesity.
2. NICE information document: https://www.nice.org.uk/news/articles/annual-bmi-checks-recommended-for-adults-with-long-term-conditions
3. NICE Consultation: https://www.nice.org.uk/guidance/indevelopment/gid-qs10183
4. Weighing device notice: https://www.nss.nhs.scot/media/5709/efa-2010-001.pdf
5. YouGov survey: https://d3nkl3psvxxpe9.cloudfront.net/documents/YouGov_-_Metric_vs_imperial.pdf