Is there a relationship between body mass index and academic achievement? A meta-analysis

Objective: To date, although there have been several systematic reviews about the relationship between overweight/obesity and academic performance, none of the reviews were conducted quantitatively, thus the extent overweight/obesity is related to academic performance still remains unclear. Thus, the aim of this study was to quantitatively review the scientific evidence on the association between body mass index (BMI) and academic performance. Study design: A systematic review of articles examining such relationship was undertaken using four databases, namely, PubMed, Web of Science, EBSCOhost and ProQuest Dissertations & Theses Global. The search period covered the research literature up to July 2017. Methods: Data from 60 selected studies (involving 164,049 participants) were extracted and analysed following procedures for meta-analysis. Results: Sixty studies met all inclusion criteria and were included. Using a random-effects meta-analysis model, a weak negative correlation between BMI and academic achievement (r = −.111; 95% confidence interval [CI]: −.155 to −.067; P <.01) was revealed. After conducting a series of moderator analyses, such a relationship was found to be significantly moderated by regions and students’ study grades. Conclusions: BMI is weakly and negatively associated with academic achievement. For a better understanding of such a relationship, future studies are needed to explore whether there is a causal relationship and also explore whether there are other factors that potentially moderate such a relationship.