Objectives: Excess free sugar consumption increases the risk of developing non-communicable diseases. Two potentially relevant antecedents of individuals’ health behaviour are knowledge and attitudes. We conducted a systematic review: (1) to identify factors influencing adults’ dietary sugar knowledge and attitudes; and (2) to determine if there is an association between adults’ dietary sugar knowledge and attitudes and free sugar intake or dietary practices.
Methods: 15 electronic databases were searched from inception for relevant articles. Peer-reviewed and grey literature published in English language and involving adults (>=18 years) were eligible for inclusion. The process of study selection followed by their quality assessments was conducted using the PRISMA guidelines and Effective Public Health Practice Project tool respectively. Findings were summarised using meta-narrative synthesis.
Results: A total of 3287 papers were identified of which 21 studies (11 for each objective) were included. Receiving nutrition education from health professionals (such as nurse, diabetes educator, or dietician) and advertising were associated with higher sugar knowledge and positive attitudes towards lower sugar consumption. In addition, lower current and past use of sugar-sweetened beverages and exposure to sugar-specific food labelling were associated with positive attitudes towards lower sugar consumption. Individuals’ attitudes towards high dietary sugar consumption were influenced by their peers. Inconsistent associations were found concerning the role of dietary sugar knowledge and attitudes in determining free sugar intake or dietary practices. The overall quality of evidence was weak.
Conclusion: Sugar consumption is complex. The findings of the available literature on determinants of dietary sugar knowledge and attitudes, and role of knowledge and attitudes in determining sugar consumption are inconclusive. More research with robust study designs investigating the role of broader determinants are warranted. This will enable the development of effective interventions and policies to promote healthy behaviours.