Using an FFQ is not always recommended as they are known to have systematic errors (measurements consistently depart from the true value in the same direction; this affects the sample mean as well as percentiles and can result in incorrect estimates and conclusions) and are limited by their food list. Please read the Strengths and Weaknesses of the different dietary assessment tools in order to ensure that the FFQ is suitable for your research question. For further information on the strengths and weaknesses, please refer to the Diet, Anthropometry and Physical Activity (DAPA) Measurement Toolkit or Dietary Assessment Primer.

Also prior to using the questionnaire in your study, please ensure that it has been validated in both the population and nutrient of interest.