Research
Mixed
Food Frequency Questionnaires (FFQ) tend to overestimate plant-derived micronutrients (like carotenes) and underestimate fat intake compared to 7-day diet diaries, but these systematic biases do not necessarily invalidate their ability to rank individuals for epidemiological purposes.
Be aware that FFQs may overestimate plant nutrient intake (like carotenes) and underestimate fat. However, for tracking trends and comparing individuals within a group, these biases are manageable and the tool remains valid for ranking purposes.
GoodQualifiesHIGH confidence
Compared with the 7DD, the FFQ tended to overestimate plant-derived micronutrient intakes... and to underestimate fat intake.
Why this rating
Directly stated with statistical significance (P<0.0001) for the differences in carotene estimation.
Source
Dietary assessment in Whitehall II: comparison of 7 d diet diary and food-frequency questionnaire and validity against biomarkers
Eric J. Brunner et al. · British Journal Of Nutrition · 2001
DOI 10.1079/bjn2001414
cross_sectional · n=860Cited 313×
Read the paper DOI resolved against Crossref · corpus check 2026-06-10
More from this paper
- A machine-readable Food Frequency Questionnaire (FFQ) provides nutrient intake estimates with validity comparable to a 7-day diet diary (7DD) when validated against biomarkers, making it a suitable tool for ranking individuals in large-scale epidemiological studies despite systematic biases in absolute intake estimation.Good
- Energy-adjusted nutrient intake analysis is the optimal method for presenting and analyzing dietary data in epidemiological studies, as it reduces bias from low energy reporting and eliminates confounding by total energy intake.Good
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