People with obesity have an increased risk of severe COVID-19: a meta-analysis by Popkin and colleagues1 found that the odds ratio of people with obesity being hospitalised with COVID-19 was 2·13 when compared with those without obesity, and mortality was 48% higher in patients with obesity than in those without. This increased risk of severe disease is linked to higher rates of metabolic and cardiovascular complications.2 Another major contributing factor is the presence of substantial immune dysregulation and chronic systemic inflammation. Obesity is associated with increased levels of numerous inflammatory mediators, including interleukin (IL)-1, IL-6, IL-17, and tumour necrosis factor α.3 These cytokines are also implicated in the pathogenesis of COVID-19.4 In addition to inflammation, obesity is associated with important defects in immune cells tasked with host protection, including natural killer cells and mucosal associated invariant T (MAIT) cells.5,6