Beyond the 24-Hour Recall: Aligning Dietary Diversity Metrics with Nutrient Physiology

Dietary diversity indicators, such as the Minimum Dietary Diversity for Women (MDD-W), are widely used to assess diet quality in low- and middle-income countries. These metrics typically rely on 24-h recall data to approximate micronutrient adequacy. Although repeated 24-h recalls can estimate usual intake distributions at the population level, they remain anchored in discrete daily intake measures that may not fully capture nutrients with episodic consumption patterns or longer physiological retention. Although the MDD-W is intended for population-level assessment, systematic misclassification at the individual level may aggregate into population-level bias. This limitation arises from insufficient alignment with nutrient biology, including variation in physiological retention, turnover, and depletion kinetics. Nutrients such as vitamin A and vitamin B-12 can be stored over extended periods, whereas others require more frequent intake. We propose a tiered recall framework that aligns dietary assessment periods with nutrient physiology, improving interpretive precision while maintaining feasibility for large-scale surveys.