Measuring effectiveness of dietetic interventions in child obesity: a systematic review of randomized trials.

OBJECTIVES: To assess the effectiveness of dietetic treatment for obese children and to report details of dietary interventions. DATA SOURCES: English-language articles from 1975 to 2003 available from health and medical databases. STUDY SELECTION: Randomized controlled trials with subjects younger than 18 years of age that included a dietary intervention in isolation or in combination with lifestyle modifications and/or psychological therapies. One person searched the databases; 2 people independently critically appraised the articles for methodological quality and then extracted data using standardized tools. DATA EXTRACTION: Thirty-seven randomized controlled trials met the inclusion criteria; 17 contained sufficient information for a Forest plot of the standardized effects. Eight studies had a true control and were included in a meta-analysis. The random effects model was reported if the Q noncombinability chi(2) statistic was significant at the 10% level because it has low power as a strict test of homogeneity. DATA SYNTHESIS: The 2 strongly qualified meta-analyses suggest that interventions that include a dietary treatment do achieve relative weight loss. Details of the dietary intervention or participant food intake are rarely described.
CONCLUSIONS: It is not possible to evaluate the effectiveness of dietary treatment for childhood obesity because of the lack of high-quality studies and the heterogeneity of designs, treatment combinations, outcome measures, and follow-up. There is an urgent need to improve the quality of studies in this area because childhood obesity poses major health risks for populations, yet there is limited evidence on which to base treatment strategies.