Global Dietary Surveillance: Data Gaps and Challenges.

Background: Detailed information on global individual-level consumption patterns is imperative for informed policy making. However, such data are dispersed and incomplete. Objective: To review and discuss the methodologies, observed data availability, challenges, and opportunities pertaining to global dietary surveillance. Methods: This investigation provides an extensive review of global dietary assessment methodologies and challenges, including at the survey level, the dietary collection and assessment level, and the dietary data processing and analysis level. The focus is on nationally representative individual-level data, and additional types of dietary data, such as dietary biomarkers, household assessment, and food availability, are reviewed as alternatives. Practical guidance is provided to inform key decisions when designing dietary surveys and collecting, analyzing, and using dietary data. This article further identifies and describes existing global and regional dietary initiatives/data sets. Results: Harmonized and standardized primary individual-level dietary data collection, processing, and analysis worldwide are currently not available. Evaluation and decision-making should be based on best available data, that is, secondary nonharmonized yet to the extent possible, standardized individual-level dietary data. Existing initiatives differ substantially in methodologies, including survey design/representativeness, coverage, diet assessment, and dietary metric standardization and processing. Data gaps have been identified that were more profound for certain countries, certain dietary indicators across countries, population subgroups, representativeness, or time periods. Conclusions: Optimizing worldwide dietary habits to improve population health requires systematically identified and evaluated data on a continuing basis. Leveraging existing available dietary data and efforts is an indispensable prerequisite for informed priority setting targeting the intersections between diet and disease.