Healthy diet metrics for children and adolescents and their suitability for global monitoring: a critical review

Background Healthy diets during childhood and adolescence are paramount for growth, development, and long-term health. However, there is a lack of low-burden standardized metrics to assess and monitor healthy diets among children and adolescents aged 2-19 years of age on a global scale.

This critical review aimed to identify and evaluate existing metrics for assessing healthy diets in this age group and to determine their suitability for global monitoring based on feasibility and adaptability across different contexts.

A systematic search was conducted across three global databases, encompassing both peer-reviewed and grey literature.

A total of 127 distinct healthy diet metrics were identified many of which were developed or adapted based on national dietary guidelines across various geographical contexts. Only five were deemed suitable for global monitoring due to their feasibility and adaptability: the Individual Dietary Diversity Score, 7 food group Minimum Dietary Diversity, 10 food group Minimum Dietary Diversity, Healthy Plate Variety Score, and Adapted ultra-processed food (UPF) Nova Score. Among these metrics, diversity was the most commonly measured sub-construct of a healthy diet, while only the Adapted Nova Score aimed to capture moderation. These five metrics were further evaluated for construct validity, reliability, and cross-context equivalence, which revealed large evidence gaps, particularly regarding sensitivity to change and test-retest reliability.

These findings highlight the need for additional research to validate healthy diet metrics globally to ensure their accuracy, sensitivity, and reliability to differentiate populations and changes over time. Developing robust, low-burden metrics is essential for informing effective, timely nutrition policies and interventions aimed at improving the diets of children and adolescents worldwide. Statement of significance This review is the first to systematically evaluate the feasibility and adaptability of existing healthy diet metrics for global monitoring among children and adolescents, identifying key gaps in their validity and reliability, particularly regarding sensitivity to change and test-retest reliability. Competing Interest Statement The authors have declared no competing interest. Funding Statement This work was supported, in whole or in part, by the Rockefeller Foundation (grant: 2022 FOD 024) and the Bill & Melinda Gates Foundation (grant: INV-063321). Under the grant conditions of the Bill & Melinda Foundation, a Creative Commons Attribution 4.0 Generic License has already been assigned to the Author Accepted Manuscript version that might arise from this submission. Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Data availability Data described in the manuscript will be made available upon reasonable request to the corresponding author. Abbreviations - DHS - Demographic and Health Surveys - FAO - Food and Agriculture Organization of the United Nations - FGDS - food group diversity score - FFQ - food frequency questionnaires - HDMI - Healthy Diets Monitoring Initiative - IDDS - individual dietary diversity score - MAR - mean adequacy ratio - MDD - minimum dietary diversity - MPA - mean probability of adequacy - QCC - Quality Criteria Checklist - UNICEF - United Nations Children’s Fund - UPF - ultra-processed foods - WHO - World Health Organization