Objective dietary assessment in nutrition epidemiology studies: Volume II

Accurately capturing what people eat and drink remains one of the greatest challenges in public health nutrition and nutrition epidemiology. Despite decades of refinement, self-report tools, such as food frequency questionnaires, diet diaries, and recalls remain prone to recall bias, under- or over-reporting, and cultural variability. These limitations introduce systematic error into diet, disease relationships, complicating causal inference and undermining reproducibility.

The first volume of this Research Topic underscored the importance of developing and validating objective dietary assessment methods, including the use of biomarkers, digital technologies, and calibration models. Volume II builds on this momentum, bringing together 21 original contributions spanning multiple continents, dietary cultures, and methodologies. Collectively, these studies illustrate the richness of approaches being pursued: novel dietary indices, validation of culturally tailored tools, population-level surveillance, and integration of nutritional biomarkers with epidemiological outcomes.