Background It is imperative that the prevention, treatment and management of overweight and obesity in children and adolescents are effective and clinicians have access to current best practice management guidelines. Since the previous review in 2003 many studies have been published investigating the effects of dietary interventions on weight outcomes in overweight children but these have not been reviewed systematically. Objectives To examine the impact of randomized controlled interventions, which include a dietary component, on weight change in overweight/obese children. Inclusion criteria Types of participants Participants who were overweight/obese subjects under 18 years of age. Types of intervention(s)/phenomena of interest Included interventions compared lifestyle interventions to no treatment/wait-list control, usual care or written education materials. Types of studies Included study designs were randomized controlled trials (RCTs) only. Types of outcomes Anthropometry, including body mass index (BMI), BMI percentile, percentage of overweight for age, waist measurement and skinfolds. Body composition, including percentage of body fat and lean body mass. Dietary measures, including energy intake, macronutrient composition and core food groups. Behavior modification, including eating behavior checklists and short-fat questionnaire. Cost. Search strategy English language articles from 2003 to 2010 available from seven databases were included in the search strategy. Methodological quality Study quality was critically appraised by two reviewers using established criteria. Data collection Two independent reviewers extracted outcome data using standardised forms. Data synthesis The findings have been presented in narrative summary, grouped by intervention characteristics. Information extracted included population demographics, method of dietary data collection, and key results on anthropometry and dietary intake. Results One hundred articles representing 70 RCTs were included. All interventions had a focus on dietary change either alone or in combination with physical activity or behavior modification including cognitive behavioral therapy (CBT). Conclusions It appears from the available evidence that a combination of lifestyle changes or a lifestyle intervention approach which incorporates a dietary component should be recommended for both future studies and clinical practice for the management of childhood and adolescent obesity. However, the quality of RCTs needs improvement, particularly with reference to bias reporting, retention rates, follow-up periods and dietary intervention reporting. The involvement of the dietician in the planning stages of pediatric weight loss trials also needs to be advocated in future studies. Further research is needed to determine the optimal length, intensity and long-term effectiveness of lifestyle interventions for pediatric obesity management.