Four instruments collect dietary data.
The Diet History Questionnaire (DHQ II) is an online food frequency questionnaire (FFQ) that asks about a list of foods eaten in the past 12 months. The frequency and quantity of these foods were recorded.
The food frequency files contain one record per food, with the two administrations split into different datasets. The nutrient file contains one record per person with an array of the two administrations. The raw questionnaire contains one record per person per administration with their responses to the questionnaire.
You may view data dictionaries and formats for the DHQ files. Datasets can be obtained by submitting a request.