Weight Management Interventions Provided by a Dietitian for Adults with Overweight or Obesity: An Evidence Analysis Center Systematic Review and Meta-Analysis

Background Obesity is associated with a multitude of comorbidities and considerable health care costs.Objective The objective of this review was to examine the efficacy of weight management interventions provided by a registered dietitian or international equivalent (referred to as "dietitian").Methods This systematic review and meta-analysis of randomized controlled trials (RCTs) examined the effect of weight management interventions provided by a dietitian, compared with usual care or no intervention, on several cardiometabolic outcomes and quality of life in adults with overweight or obesity. MEDLINE, Embase, PsycINFO, Cochrane CENTRAL, Cochrane Database of Systematic Reviews, and CINAHL databases were searched for eligible RCTs published between January 2008 and January 2021 in the English language. Meta-analyses were conducted using a random-effects model, publication bias was assessed using funnel plots and Egger's statistics, and heterogeneity was assessed by interpreting I2 values. Efficacy of intervention components, such as telehealth or group contacts, were explored in sub-group analyses. Version 2 of the risk-of-bias tool for RCTs was used to assess risk of bias. The Grading of Recommen-dations Assessment, Development and Evaluation method was used to determine certainty of evidence.Results This systematic review included 62 RCTs. Compared with control conditions, weight management interventions provided by a dietitian resulted in improved body mass index (mean difference [MD] -1.5; 95% CI -1.74 to -1.26; moderate evidence certainty); percent weight loss (MD -4.01%; 95% CI -5.26% to -2.75%; high evidence certainty); waist circumference (MD -3.45 cm; 95% CI -4.39 to -2.51 cm; high evidence certainty); blood pressure (MD -3.04 mm Hg; 95% CI -5.10 to -0.98 mm Hg and MD -1.99 mm Hg; 95% CI -3.02 to -0.96 mm Hg for systolic blood pressure and diastolic blood pressure, respectively; moderate and low evidence certainty); and quality of life using the 36-Item Short Form Survey (MD 5.84; 95% CI 2.27 to 9.41 and 2.39; 95% CI 1.55 to 3.23 for physical and mental quality of life, respectively; low and moderate evidence certainty).Conclusions For adults with overweight or obesity, weight management interventions provided by a dietitian are efficacious for improving several examined cardiometabolic outcomes and quality of life.J Acad Nutr Diet. 2023;123(11):1621-1661.