Many self-directed weight-loss interventions have been developed using a variety of delivery formats (e.g., internet and smartphone) and change techniques. Yet, little research has examined whether self-directed interventions can exclusively promote weight loss. MEDLINE, Embase, PsycINFO, CINAHL, and the Cochrane Library were systematically reviewed for randomised controlled trials evaluating self-directed interventions in relation to weight-loss outcomes in adults. Standardised mean differences (SMD) and 95% confidence intervals (CI) were calculated using a random effects model. Twenty-seven trials incorporating 36 comparisons met our inclusion criteria. Participants using self-directed interventions lost significantly more weight (MD = -1.56 kg, CI -2.25, -0.86 ranging from 0.6 to 5.3 kg) compared to those in the minimal intervention or no-treatment groups (3.1-month follow-up median). The majority of interventions were internet based (18 evaluations) and these were effective at 3 months (MD = -1.74 kg, CI -2.65, -0.82 ranging from 0.6 to 4.8 kg) (SMD = -0.48, 95% CI -0.72, -0.24, I(2) = 82%; p < .0001; 16 evaluations) and 6 months follow-up (MD = -2.71 kg, CI -4.03, -1.39 ranging from 2.2 to 5.3 kg) (SMD = -0.59, 95% CI -0.99, -0.19, I(2) = 76%; p = .004; 4 evaluations). Self-directed weight-loss interventions can generate modest weight loss for up to 6 months but may need to be supplemented by other interventions to achieve sustained and clinically meaningful weight loss.
Keywords: Weight loss; eHealth; meta-analysis; obesity; self-delivered intervention; systematic review.