The food frequency questionnaire method is more time-, cost- and labor-effective than the 24-h dietary recall and recording method. Such a food frequency questionnaire based on food groups is more convenient than one using a food list, because there are fewer questions.
We have developed a food frequency questionnaire (FFQg), which is based on 29 food groups and 10 types of cooking, for estimating the energy and nutrient intakes of an individual subject during the past 1-2 months. This questionnaire was evaluated by comparing with weighted dietary records for 7 continuous days (7-d records) for 66 subjects aged 19-60 years.
The correlation coefficients between FFQg and the 7-d records for the energy, protein, fat, carbohydrate and calcium intakes were 0.47, 0.42, 0.39, 0.49 and 0.41, respectively. The intakes of 26 of 31 nutrients were not significantly different by a paired t-test between the two methods (p≥0.05). The ratio of the value obtained by the FFQg method against that by the 7-d record method ranged from 72% (vitamin B12) to 121% (niacin), the average ratio being 104%.
The correlation coefficients for the intakes of rice, bread, meat, fish, milk, dairy products, green-yellow vegetables, other vegetables, and fruits were 0.66, 0.76, 0.27, 0.27, 0.72, 0.58, 0.46, 0.53, and 0.64, respectively, between the FFQg and 7-d record methods, and there was significant correlation between the two methods at the p<0.05 level for 22 of the 29 food groups.
Apart from those food groups for which “less than once a month or never” was selected by 50% respondents or more, 34% of the respondents could estimate a portion size in the FFQg with an error of less than 25%, indicating that this FFQg is a useful instrument for estimating individual energy and nutrient intakes.