Food Frequency Questionnaire (FFQ)
What It Measures
A food frequency questionnaire is a checklist of foods and drinks with response options for how often a person usually eats each one. It is not a food diary — nobody records what they ate yesterday. Instead it asks about typical habits over a longer stretch, usually the past month, three months, or year.
Covering the whole diet takes 80 to 120 items. Some versions ask only how often; others also ask about portion size, which is what allows nutrient estimates when the answers are matched to a food composition database. Most are self-completed. Because it captures usual intake over time, an FFQ picks up foods eaten occasionally — the ones a single day's recall would miss entirely.
Further Reading
Additional Notes
Licensing Notes: There is no single FFQ. It is a method, and dozens of specific instruments use it — Confirm terms for whichever specific questionnaire you use.
Learn More: Two limitations matter clinically. FFQs are subject to substantial measurement error and to flat-slope syndrome — people with high intake tend to under-report and people with low intake to over-report — so an FFQ is better at ranking people relative to each other than at estimating any one person's absolute intake.
