The SHED-IT weight loss maintenance trial protocol : a randomised controlled trial of a weight loss maintenance program for overweight and obese men

Despite short-term efficacy, many weight loss studies demonstrate poor long-term results and have difficulty recruiting men. Cost-effective treatments that help men achieve long-term weight loss are required. Using a two-phase, assessor-blinded, parallel-group randomised controlled trial design this study will test the effectiveness and cost-effectiveness of a male-only weight loss maintenance intervention. In Phase I (3 months) 209 men received the SHED-IT Weight Loss Program. In Phase II (12 months) 92 men who lost 4 kg or more were randomised to either (i) a maintenance group who received the 6-month, gender-tailored SHED-IT Weight Loss Maintenance Program, which included no face-to-face contact (n = 47), or (ii) a self-help control group (n = 45). Randomisation was stratified by weight loss (4 kg–7.4 kg, ≥ 7.5 kg) and BMI (< 30 kg/m², ≥ 30 kg/m²). Assessments occurred at 'study entry' (start of Phase I), 'baseline' (start of Phase II), '6 months' (post-test) and will occur at '12 months' (follow-up; primary endpoint). The primary outcome is weight change in Phase II (i.e. from 'baseline' at 12 months after randomization). Secondary outcomes include waist circumference (umbilicus and narrowest), blood pressure, body composition, objectively measured physical activity, sedentary time, portion size, dietary intake, quality of life, depressive symptoms, and behavioural cognitions. Costing data will be collected for cost-effectiveness analysis. Generalised linear mixed models (intention-to-treat) will assess outcomes for treatment (maintenance vs. control), time (baseline, 6-month and 12-month) and the treatment-by-time interaction. This will be the first study to evaluate a male-only, gender-targeted weight loss maintenance program. Results will provide evidence regarding feasible and theoretically-driven obesity treatments for men with potential for long-term impact and widespread dissemination