The Influence of Factors on Accuracy of Reported Dietary Intake

The purpose of this study is to investigate the influence of the interaction among dietary restraint, social desirability, and food type ("healthy" vs. "unhealthy") on the accuracy of reporting consumption of a laboratory meal during a 24-hour dietary recall. The automated multiple-pass method (AMPM) of 24-hour dietary recall is considered the gold standard of dietary assessment however the potential for error and biases is widely acknowledged with a tendency towards underreporting. Underreporting has been linked to many factors including two individual characteristics, dietary restraint and social desirability. Both dietary restraint and social desirability have been extensively studied however the influence of their interaction on reported dietary intake is not fully understood. In addition, a relationship to the types of foods (healthy vs. unhealthy) has also been found. For this study, 40 normal-weight female participants will be recruited at The University of Tennessee using flyers inviting volunteers. Participants will be categorized by dietary restraint, high or low, and social desirability, high or low, based on questions during the initial screening. In a laboratory setting participants will consume a meal of pre-weighed foods, including both "healthy" and "unhealthy" foods. The following day, an AMPM 24-hr dietary recall will be conducted with the participant over the telephone. Accuracy of the reported dietary intake of the laboratory meal will be determined by the equation \[(reported intake - measured intake)\]/measured intake\] x100 for amount (weight or volume) and energy (kilocalories) with comparisons between groups and within food types using mixed factorial analysis of variance.