|Inclusion criteria||Exclusion criteria|
|Population: direct supply-side stakeholders with a role in menu labelling implementation (e.g. food service business staff and management, caterers).||Population: demand side stakeholders (e.g. consumers) and indirect supply-side stakeholders (e.g. suppliers, policy makers, guideline developers, health professionals).|
|Intervention: no restriction on menu labelling format (numeric or interpretive), scheme (voluntary or mandatory) or type of food service business.||Intervention: menu labelling as part of a multi-component intervention.|
|Type of research: all primary research studies (from grey or peer-reviewed literature) using qualitative, quantitative or mixed methods approaches.||Type of research: editorials, commentary and opinion pieces.|
Language and publication year: no restrictions.|
Outcome: any barrier or facilitator to the implementation of menu labelling interventions.