Dietary Assessment Study - An evaluation study to assess validity and acceptability of a new smartphone-based dietary assessment method

Accurate dietary assessment is essential in nutrition research. The mainstay of
dietary assessment consists of food records (FRs), 24-hour recalls (24hRs), and
food frequency questionnaires (FFQs). However, they are charged with a range of
drawbacks such as measurement error and a large burden on participants.
Therefore, there is a growing interest in more technology-based dietary
assessment methods (e.g. online tools, smartphone applications), which have the
potential to improve accuracy and reduce participant*s burden. To collect food
intake data in a faster, more flexible, and more reliable manner, we developed
an innovative 2-hour recall (2hR) smartphone app (i.e. *Traqq*). A 2-hour
reporting period should minimize the reliance on memory thus increasing
accuracy of the reports. This should also lower participant burden as only a
few items have to be recorded at once.

The main objective of DIASS is to evaluate the ability of the smartphone-based
2hR app *Traqq* to accurately assess the actual and usual intake of food
groups, foods, energy and nutrients (i.e., macro- and micronutrients) while
using different interval schemes. The secondary objective is to gain insight in
the level of acceptability (incl. perceived burden) and compliance of the
different interval schemes.

The DIASS study has a cross-over design with two experimental conditions
divided over six groups; i.e. measuring actual intake and habitual intake.
Within the actual intake condition, subsamples will be created (i.e. groups 2,
3, 5, 6). The participants will be randomly assigned to one of six groups.

In one period, all participants will be asked to complete three full-day 2hRs
(i.e. 3x8 prompts), three 24hRs, either web-based (180 participants) or via
telephone (40 participants), and additionally 100 participants will asked to
collect two 24-h urine samples and for two venapunctures. During the other
period all participants will receive twenty-four random 2hRs and complete one
FFQ. The study periods will be in random order. All participants will be asked
to fill in one questionnaire on personal characteristics and one evaluation
questionnaire. The 24hRs and FFQ will take about 30 minutes while responding to
the prompts will take on average 5 minutes. The additional questionnaires will
take no longer than 15 minutes and all questionnaire will be administered
online. Venapunctures can occasionally cause a local hematoma or bruise and
some participants may report pain or discomfort