Validity of a food frequency questionnaire varied by age and body mass index

Background and Objective The validity of food frequency questionnaires (FFQs) in measuring food consumption and nutrient intake has to be assessed. The objective of this study was to assess the validity of a 128-item FFQ in specific subgroups of Finnish adults. Methods The study included 294 subjects (137 men and 157 women). A 3-day food record was used as the reference method. Results The mean intake of all nutrients except alcohol was higher...