FFQ

The Food Frequency Questionnaire is a self-administered dietary assessment tool designed to measure habitual food and nutrient intake over an extended period (typically 6–12 months). Developed by epidemiologists, particularly Walter Willett at Harvard, the FFQ has become a cornerstone of nutritional epidemiology research, enabling large-scale studies to assess dietary patterns and examine diet-disease relationships. FFQs vary in length (50–200+ items) and focus, but all share the purpose of estimating average dietary intake in a time-efficient manner suitable for population studies.