OBJECTIVE:There is recent evidence that poor health literacy (HL) could be implicated in the aetiology of obesity and could be an important reason behind obese people's inability to encounter difficulties in overcoming obesity issues. The current study reviews the recent scientific evidence investigating the possible link between poor HL levels and excess body weight in adults and children. METHODS:The authors performed a thorough systematic computer-assisted literature search from 1 January 2005 up to 31 May 2017. Only English original studies in healthy people, investigating the relationship between HL and excess body weight, were included. RESULTS:Twenty-two studies in total were included in this literature review, 17 studies were conducted in adults and 5 in children. In 17 out of 22 studies reviewed, low HL was significantly associated with increased body mass index, overweight and obesity. In case of children and adolescents, the above association seems to be more consistent compared to adults. CONCLUSION:There is good evidence that low levels of HL are associated with excess body weight, particularly in children. Initiatives to improve health literacy levels could be a useful tool in the management of the obesity epidemic.