Obesity Abstracts

Background: Robust assessment of the association between diet and health in population-based studies requires accurate and often repeated measurements of diet. The use of 24h dietary recalls can provide more accurate intake data than questionnaires, with reduced measurement error. Online dietary assessment tools can reduce administrative costs and facilitate repeated dietary assessment during follow-up in research or in clinical populations. We have developed an online dietary assessment tool, myfood24, undertaken validation comparing results to biomarkers and tested in clinical populations.

Method: A validation study recruited metabolically stable adults who completed myfood24, an interviewer administered multiple pass dietary recall and a suite of reference measures on 3 occasions. A further mixed methods study was undertaken to explore the feasibility and usability of myfood24 as a food record in a clinical population, women with gestational diabetes (GDM). Women were asked to complete five myfood24 food records, followed by a user questionnaire (including the System Usability Scale (SUS), a measure of usability), and were invited to participate in a semi-structured interview.

Results: In the validation study biomarkers were received from 212 participants. myfood24 gave broadly similar results to the more administratively burdensome interviewer-based tool. The online tool resulted in attenuation factors of around 0.2–0.3 which could have important effects on estimated risks. For example, if the true relative risk of a diet-disease association was 2.0, an attenuation factor of 0.3 would reduce the relative risk to 1.23. The clinical study recruited 199 participants with mean booking body mass index 29.7 kg/m², of these 121 women completed myfood24 at least once. The SUS was good at 71/100. Interviews identified areas for improvement, including optimisation for mobile devices and as a clinical management tool.

Conclusion: The less burdensome use of the online tool, with automated nutrient coding and easy replication over a longer time period with associated gains in precision, makes it well-placed for repeated use in large-scale prospective studies and clinically. Ongoing work is exploring the use of myfood24 in clinical dietetic practice.

Keywords: Dietary assessment, online

Disclosures: JC is director of Dietary Assessment Ltd.