School Gardening Activities Aimed at Obesity Prevention Improve Body Mass Index and Waist Circumference Parameters in School-Aged Children: A Systematic Review and Meta-Analysis

Background: Childhood obesity, due to its increasing prevalence, is one of the most challenging problems in public health and prevention. Recent strategies have been implemented to tackle this trend, including school gardening projects. This systematic review analyzes the main elements of school gardening with a specific meta-analysis about its impact on anthropometric parameters. Materials and Methods: We searched studies in PubMed, EMBASE, and Cochrane Library on school gardening projects carried out until February 2019 and addressed to children aged 6 to 13 years. Results: Thirty-three studies passed the screening selection. Outcomes analyzed were fruits and vegetables consumption/knowledge, nutritional attitudes and behavior, anthropometric outcomes (i.e., BMI, waist circumference-WC) and other outcomes (i.e., blood pressure, science achievement, and physical activity). We performed descriptive analyses of these outcomes and found a general benefit from school gardening projects. We subsequently performed a meta-analysis on anthropometric outcomes, highlighting a significant reduction of both BMI percentile (%) (-1.37%) and WC (-1.30 cm). Conclusions: Although more high-quality studies are needed on this topic, along with a greater homogeneity of anthropometric measurements, the results of our article show a modest but positive impact of school gardening projects on anthropometric measures and more generally on children's health.