

#523: How Trustworthy is the Food Frequency Questionnaire in Evaluating Dietary Intake? – Deirdre Tobias, ScD
May 21, 2024
Deirdre Tobias, an expert in nutritional research, discusses the reliability and limitations of the Food Frequency Questionnaire for evaluating dietary intake in nutrition research. Topics include the purpose of FFQ, challenges of self-reported data, validation methods, and strategies to enhance reliability in capturing habitual dietary behaviors over an extended period.
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FFQs Are Population- and Purpose-Specific
- There is no single FFQ; questionnaires are population- and hypothesis-specific and must include foods contributing key nutrients.
- Foods are mapped to nutrient databases so investigators estimate nutrient intakes by summing across items.
Harvard FFQ Validated With Repeated Records
- The original Harvard FFQ was validated by comparing it to repeated weighed diet records over a year.
- That validation showed FFQs rank individuals well for many nutrients, but performance varies by nutrient.
Precision Versus Scalability Trade-Off
- FFQs trade precision for scalability and lower participant burden compared with weighed records.
- Use the tool whose precision matches the question; FFQs are fine for ranking habitual exposures but not for ultra‑precise measurements.