Background UK Armed Forces (UK AF) veterans may be particularly vulnerable to obesity and its comorbid physical and mental health problems.

Aim To examine the relationship between body mass index (BMI), physical health problems, mental health disorders and sociodemographic characteristics in UK AF veterans engaged in psychological treatment.

Methods Information regarding veteran BMI, demographic characteristics, physical health conditions and mental health problems was collected and analysed using univariate and multivariate regression analyses. Rates of veteran obesity were also compared with the UK general population.

Results Of the 384 help-seeking veterans, 37.5% (n=151) were overweight (BMI 26–30) and 35.5% (n=143) were obese. Obesity in help-seeking male veterans was two to four times higher than that of the general population of UK. Higher scores on measures of anger and common mental health problems were significantly associated with greater BMI. Problems with physical systemic functioning and mobility were also significantly associated with greater BMI.

Conclusions The results indicate that treatment-seeking UK AF veterans exhibit higher levels of obesity compared with the general population, and clinically significant physical and mental comorbidities. The findings highlight a need for mental health services to offer treatments that effectively integrate physical and mental healthcare in the treatment of people with mental health problems.