Dietary assessment - Duplicate Diets
The duplicate method of dietary assessment is when a duplicate portion of all food and drink consumed throughout the day is retained. The identical portions are weighed, by the respondent (or fieldworker) and usually a concurrent weighed diet diary is maintained. All food is chemically analysed by bomb calorimetry. Sometimes, multiple days of assessment may be combined into a single composite, and then homogenised before analysis; this does not provide data on within-person variation.