Acceptability and preference of the two dietary assessment methods
As illustrated in 
Preferred methodFor the 24 h DR, it was especially the memory of food intake and portion sizes that was evaluated as difficult. Therefore, participants were happy to have the interview appointments beforehand, so they could quickly recall what they had eaten the day before – before the interviewer called. Participants felt that the questioning and probing throughout the interview, especially about details, made them report more foods and details such as butter on bread and sugar in coffee during the 24 h DR than in the7 d FD reporting. The FMB was seen as awkward because it had an abnormal size. Some thought it was difficult to use for portion size estimation. The mounds on the plate and the grid model were not easy to use; it was easier with realistic pictures, as in the 7 d FD instead of arbitrary forms. However, it was helpful that the forms were real sizes.Participants evaluated both methods as both cumbersome and easy. The 7 d FD was evaluated as cumbersome because it had to be completed every day for 7 consecutive days with searching, clicking and writing, and the 3 × 24 h DR because of the fixed times for the interviews and the long interview with repetitive questions. The interviewers also experienced that some participants were annoyed by the repetitive questions, but they also experienced that many participants came up with more foods eaten when asked about often-forgotten foods and food and drinks between meals. In general, the interviewers experienced that the participants had difficulties using the FMB because of the many options and the scrolling needed to find the most suitable model.