Food frequency questionnaire (FFQ) is a dietary assessment tool delivered as a questionnaire to estimate frequency and, in some cases, portion size information about food and beverage consumption over a specified period of time, typically the past month, three months, or year.
A FFQ that aims to capture total dietary intake includes questions on 80 to 120 food and beverage items, and takes 30 to 60 minutes to complete.
[citation needed] FFQs are classified as:[11][10] FFQ is a common method for dietary assessment, i.e., for constructing the respondent's diet history.
[10] One disadvantage of FFQs and other retrospective methods is that they may be less accurate because participants are relying on memory rather than information recorded in real time.
In a typical research design, the FFQ is validated against another dietary assessment technique (such as 24-hour diet recall or weighted food records) on a small population.
Walter Willett, developer of the Harvard FFQ, estimated a correlation of 0.60 to 0.70 between standard FFQs and diet recalls.
[38] Alan R. Kristal, Ulrike Peters and John D. Potter wrote in their article "Is It Time to Abandon the Food Frequency Questionnaire?"
that there was not much scope to learn more from FFQs, and that a more curious and exploratory approach was needed to uncover new insights on diet and its correlation with health status.