Background/objective:To investigate the extent of baseline psychosocial characterisation of subjects in published dietary randomised controlled trials (RCTs) for weight loss.Subjects/methods:Systematic review of adequately sized (n≥10) RCTs comprising ≥1 diet-alone arm for weight loss were included for this systematic review. More specifically, trials included overweight (body mass index >25 kg/m 2) adults, were of duration ≥8 weeks and had body weight as the primary outcome. Exclusion criteria included specific psychological intervention (for example, Cognitive Behaviour Therapy (CBT)), use of web-based tools, use of supplements, liquid diets, replacement meals and very-low calorie diets. Physical activity intervention was restricted to general exercise only (not supervised or prescribed, for example, VO 2 maximum level).Results:Of 176 weight-loss RCTs published during 2008-2010, 15 met selection criteria and were assessed for reported psychological characterisation of subjects. All studies reported standard characterisation of clinical and biochemical characteristics of subjects. Eleven studies reported no psychological attributes of subjects (three of these did exclude those taking psychoactive medication). Three studies collected data on particular aspects of psychology related to specific research objectives (figure scale rating, satiety and quality-of-life). Only one study provided a comprehensive background on psychological attributes of subjects.Conclusion:Better characterisation in behaviour-change interventions will reduce potential confounding and enhance generalisability of such studies.