An updated systemic review from the Cochrane Library.
Conclusions: There is limited high quality data on the effectiveness of obesity prevention programs and no generalisable conclusions can be drawn. However, concentration on strategies that encourage reduction in sedentary behaviours and increase in physical activity may be fruitful. The need for well-designed studies that examine a range of interventions remains a priority, although a number of important studies are underway.
Source: The Cochrane Library, Issue 4, 2004