Validity of the 24-hour dietary recall.

The validity of the 24-hour recall was studied with a comparison of recalled and observed food and nutrient intake for 140 subjects, 84 males (60%) and 56 females (40%), 15 to 57 years old. The observation was carried out during 1 day by recording the amounts of foods selected by the subjects at four meals. The following day, 24-hour recalls were obtained. The results showed that some food items eaten were omitted in the recall, the extremes being 4% of times eaten for fish and 50% for cooked vegetables. In addition, some food items not actually eaten were added in the recall, the additions ranging from 2% of times recalled for bread to 29% for sugar. The difference between mean recalled and observed nutrient intake was between -6% and 11%, except for sucrose (-20%) and vitamin C (-16%). The product-moment correlation coefficient between observed and recalled nutrient intake was in the range of 0.58 to 0.74. Women achieved somewhat more accurate results than men, and the recall results in the 35 to 44 age group were the most valid. It was concluded that validity is unsatisfactory on the individual level and satisfactory on the group level.