Production and validation of a food frequency questionnaire to estimate dietary fat intake

A quantitative 92-item food frequency questionnaire (FFQ), using photographs to estimate portion size, was developed from a 180-item FFQ and validated by comparison with weighed dietary records of 80 adults. The main aim of the FFQ was to classify subjects according to their fat intake as a percentage of total energy intake. Correlation coefficients and classification of individuals into thirds for fat (g), percentage energy from fat and total energy, showed good agreement between the FFQ and the diet record. There was significant difference in the mean percentage energy from fat but not in grams of fat or total energy intake estimated by the two methods. Intra-class correlation coefficients indicated a significant relationship between an individuals' percentage energy from fat estimated by the FFQ and diet records. These results suggest that the FFQ was suitable for classifying individuals into groups based on their percentage energy from fat and for estimating the actual average fat and energy intake of groups, and that the FFQ may be useful for estimating the percentage energy from fat for an individual.