1 School of Human Nutrition, Faculty of Agricultural and Environmental Sciences, McGill University, Macdonald Campus, Ste-Anne-de-Bellevue, Quebec, Canada.
2 PERFORM Centre, Concordia University, Loyola Campus, Montreal, Quebec, Canada.
3 Department of Psychology, Concordia University, Loyola Campus, Montreal, Quebec, Canada.
4 Faculty of Land and Food Systems, Food, Nutrition and Health, Dietetics, the University of British Columbia, Vancouver Campus, Vancouver, British Columbia, Canada.

Background: Self-monitoring is an important behavioral change technique to help users initiate and maintain dietary changes. Diet self-monitoring tools often involve the itemization of foods and recording of serving sizes. However, this traditional method of tracking does not conform to food guides using plate-based approach to nutrition education, such as the 2019 Canada's Food Guide (CFG).

Objective: To explore the acceptability, facilitators and barriers of using a plate-based dietary self-monitoring tool based on the 2019 CFG (Plate Tool) compared with a traditional Food Journal (Food Journal).

Methods: The 2 dietary self-monitoring tools were compared using a crossover study design over 2 wk. Adults over 50 (n = 47) from Montreal, Canada, were randomly assigned to use one tool over 3 d during 1 wk, then used the other tool the next week. Semistructured interviews (n = 45) were conducted after completing the second tool. A qualitative description of the interviews was conducted through an inductive determination of themes.

Results: Facilitators to using the Plate Tool were its simplicity, quick completion time compared with the Food Journal and easiness to use, increased awareness of dietary habits and accountability, with participants expressing that it could help users make informed dietary changes aligning with the CFG. However, barriers to using the Plate Tool were its lack of precision, the participants' difficulty categorizing foods into the CFG categories and recording intake of foods not present on the CFG.

Conclusions: The Plate Tool is an acceptable dietary self-monitoring tool for healthy adults over 50. Self-monitoring tools based on the plate method should take the barriers described in this study into account. Future studies should compare dietary self-monitoring methods to assess adherence and effectiveness at eliciting dietary behavior change.