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©British Journal of General Practice. Background: Guidelines suggest that GPs should intervene on patients' weight, but to do so GPs must first recognise that a patient may have a weight problem and weigh them. Aim: To examine whether GPs and trainee GPs can identify overweight and obese body weights by sight, and if this influences whether they would discuss weight with a potential patient. Design and setting: Study of GPs and trainee GPs on the lists of the UK NHS Workforce West Midlands Deanery and NHS Sandwell and West Birmingham Clinical Commissioning Group. Method: Participants viewed 15 standardised photographs of healthy-weight, overweight, and obese young males, and estimated their BMI, classified their weight status, and reported whether they would be likely to make a brief intervention for weight loss with that person. Results: The sample of GPs and trainee GPs correctly classified a mean of 4.0/5.0 of the healthy weight males, a mean of 2.4/5.0 of the overweight, and a mean of 1.7/5.0 of the obese males. For each 1 kg/m2 increase in actual BMI, participants underestimated BMI by -0.21 (95% CI = -0.22 to -0.18), meaning that participants would underestimate the BMI of a man of 30 kg/m2 by approximately 2.5 kg/m2, but were more accurate for lower body weights. Participants were more likely to intervene with those with a higher estimated BMI (OR 1.53, 95% CI = 1.49 to 1.58). Conclusion: This sample of predominantly trainee GPs perceived overweight and obese weights as being of lower BMI and weight status than they actually are, and this was associated with a lower intention of discussing weight management with a potential patient. This was found to be true for trainee and fully qualified GPs who participated in the study. Healthcare professionals should not rely on visual judgements when identifying patients who may benefit from weight management treatment.

Original publication




Journal article


British Journal of General Practice

Publication Date





e703 - e708