How is food variety conceptualised and measured as a diet quality indicator in developed settings? Protocol for a systematic scoping review

OBJECTIVES: Dietary diversity (DD) is a pillar of healthy eating guidance and can be used to assess diet quality. Despite being an established nutrition concept, many inconsistencies in its definition and measurement exist and meanings vary across the development spectrum. This protocol outlines a research trajectory, whereby a scoping review will be undertaken to illustrate and map the methodological approaches that have been utilised to measure diversity as a marker of diet quality in the general population. It seeks to determine the most common and less used methodological approaches to measure DD in the diet of healthy adults. METHODS AND ANALYSIS: Scoping review of peer-reviewed and grey literature from five bibliographic databases, supplemented by handsearching of reviews and reference lists. Search terms will include DD, food variety, mixed diet, balanced diet and food group variety. Eligible articles must include a measure for DD as an indicator of diet quality in the general population living in developed settings. Two independent reviewers will screen titles or abstracts, and read full-texts. Consensus will resolve any disagreements on study eligibility with a third reviewer consulted if needed. Data will be extracted using a standardised evidence table and analysed using a narrative synthesis approach. Data will be managed using Covidence. ETHICS AND DISSEMINATION: No ethics is required for this study using public documents. Results will be disseminated through peer-reviewed papers and scientific conferences. DISCUSSION: This scoping review will help to map, classify and assess the methodological approaches used in the nutrition literature to measure DD as a diet quality indicator. We anticipate a wide range of DD measures and expect to identify the most prevalent DD measures used to assess diet quality. Our findings will inform standardisation to improve future research on this nutritional concept.