OBJECTIVES: Rates of overweight and obesity in the UK are expected to increase over the coming years; however, the projected burden stratified by body mass index (BMI) category is less frequently reported. We estimated the prevalence of overweight and obesity classes, and associated costs and health outcomes, in the UK from 2020–2033.

METHODS: The analysis considered adults aged ≥20 years, defined as having overweight (BMI 25–<30 kg/m²), or obesity class I, II or III (BMI 30–<35 kg/m², 35–<40 kg/m² or ≥40 kg/m², respectively). Future prevalence was projected based on 2022 World Obesity Atlas estimates, combined with Office for National Statistics population projections and BMI category prevalence estimates from the 2021 Health Survey for England. Obesity prevalence was assumed to increase linearly over time. Annual per-person costs and major adverse cardiovascular events (MACE; a composite of acute myocardial infarction, stroke and cardiovascular death) were calculated using 2019 data from the Discover electronic health record data set, which covers 2.8 million people living in North West London.

RESULTS: Approximately 50 million individuals are expected to be living with overweight and obesity in the UK in 2033 (a 48% increase from 2020), corresponding to an additional 9.3 million people with overweight and 7.1 million with obesity (class I: 4.7 million; class II: 1.6 million; class III: 0.8 million). In the period 2020–2033, an estimated £10 billion in healthcare costs (a 48% increase from 2020) and 54,416 MACE events (a 65% increase from 2020) will result from this increase in the prevalence of obesity.

CONCLUSIONS: Increases in overweight and obesity in the UK over the coming decade have implications for healthcare systems, affected individuals and the wider economy. Predicting these trends can help to identify areas of unmet need for weight management support.