Data on the prevalence of obesity in Wales and its evolution over time, is crucial to ensuring that appropriate funding and resources are directed towards tackling this social challenge. This data can also help to target interventions towards specific geographic areas and groups. Finally, this data is critical for monitoring the progress and effectiveness of interventions, and thereby helping policymakers to understand what works best and for whom.
The most significant challenge in regards to measuring obesity is the potential for bias if we either rely on self-reported data (where respondents tend to underestimate their weight), or if we rely on data from GP visits (which represent a non-random sample of the population). While the Healthy Weight, Healthy Wales 2022 - 2024 delivery plan makes a commitment to ‘improve systematic collection and access to primary care data regarding height and weight’(p.22), no detailed plans on how this will be achieved have been made public.
Overcoming the biases in weight data would require objectively measuring weight for a representative sample; potentially as part of the National survey for Wales (this is already the case for England and Scotland’s national health surveys). However, this process can be time-consuming and costly. Finally, any measurement programme must be carried out sensitively and cautiously, given the potential for perpetuating weight stigma and associated harms.
Other data gaps that have been identified could also potentially be addressed by drawing on existing infrastructure; for example, by extending the Child Measurement Programme (which recurrently only collects BMI data for reception-age children), to include older primary school and secondary school children.
“There is still a lot that we don't know. We know an awful lot about obesity and being overweight and the causes of it, but we don't really have a very clear understanding, in Wales at least, of the point at which children start to become overweight.”
Reducing the prevalence of obesity
