Association of Plate Design With Consumption of Fruits and Vegetables Among Preschool Children

Children in the United States do not consume enough fruits and vegetables.¹ One potential approach to change health behaviors such as fruit and vegetable consumption is to change the decision environment to make certain behavior more likely without altering incentives.^2,3 For example, placing pictures of fruits and vegetables on lunch trays is associated with an increase in fruit and vegetable consumption among school-aged children.⁴ This potentially powerful intervention, however, has not been explored among children in early childhood (3-8 years of age), and dietary behavior during this period can be associated with life-long dietary practices.⁵ This study addresses this gap and tests the association between use of plates with fruit and vegetable pictures and consumption of fruits and vegetables among preschool children between 3 and 5 years of age.

We conducted a field experiment among 235 children (50.64% female; mean age [SD], 3.80 [0.65] years) in 18 classrooms within a preschool in Arvada, Colorado. Individual informed consent was waived by the University of Colorado Institutional Review Board, which approved all study procedures. The experiment used a 2 (intervention period) × 3 (day) completely crossed within-participant design. Baseline and intervention periods each consisted of 3 school days in a 1-week period, and the intervention occurred 4 weeks after baseline. Lunch menus were identical in both periods. Plates with sections for fruits and vegetables designated by pictures served as the intervention, compared with white plates during the baseline period. We also gave a 5-minute introduction of the intervention plate during day 1 of the intervention to confirm that the children understood that the pictures indicated designated sections for fruits and vegetables. Children ate lunch in their classrooms and served themselves from bowls of fruits and bowls of vegetables. On average, serving bowls contained 830.24 g of fruit and 583.14 g of vegetables per classroom. We weighed the fruit and vegetable bowls before and after lunch and calculated the difference to determine the amount of fruits and amount of vegetables taken. We then subtracted the total weights of uneaten fruits and uneaten vegetables from the total amounts taken in each classroom to compute the total amount of fruits eaten and total amount of vegetables eaten. We divided these 4 outcome variables by the number of children in each classroom to determine mean amount of fruits taken, fruits consumed, vegetables taken, and vegetables consumed per child in each classroom (18 classrooms). We conducted 2 (intervention period) × 3 (day) repeated-measures analysis of variance on vegetables taken and eaten and 2 (intervention period) × 2 (day) repeated-measures analysis of variance on fruits taken and eaten (the lunch menu on day 2 did not include fruit). Two-sided P values are reported.

Segmented plates with pictures were associated with significant increases in both the amount of vegetables taken and the amount of vegetables consumed per child per day, but they were not associated with an increase in the amount of fruits taken or consumed (Figure). Children in our cohort took a greater mean amount of vegetables per child per day during the intervention period (43.51 g; 95% CI, 37.97-49.05 g) compared with baseline (29.69 g; 95% CI, 27.20-32.18 g), an increase of 13.82 g (P < .001). They also consumed a greater mean amount of vegetables per child per day during the intervention period (28.17 g; 95% CI, 24.03-32.32 g) compared with the baseline period (20.63 g; 95% CI, 17.81-23.44 g), an increase of 7.54 g (P = .001). Intervention also interacted with day for both vegetables taken and vegetables consumed (P < .001), with the strongest intervention effect on day 2, when the lunch menu included cucumbers and carrots. Both the amount of fruits taken and the amount of fruits consumed increased during the intervention period, but these increases did not reach statistical significance. The mean amount of fruit taken was 60.05 g per child per day (95% CI, 54.12-65.99 g) during the baseline period vs 63.71 g per child per day (95% CI, 59.47-67.95 g; P = .34) during the intervention period; the mean amount of fruit consumed was 50.84 g per child per day (95% CI, 43.28-58.39 g) during the baseline period vs 54.88 g per child per day (95% CI, 48.63-61.12 g; P = .36) during the intervention period.

The results of our study indicate that fruit and vegetable pictures on segmented lunch plates may be associated with an increase in vegetable consumption among children who are 3 to 5 years of age. We did not observe a comparable association with fruit consumption, and a possible explanation for this finding is a ceiling effect. At baseline, children took 88.5% of fruits available, compared with 65.4% of vegetables available. One limitation of the study was the relatively small sample size, but this was compensated for by the longitudinal design with matched menus. Because early childhood dietary behavior has been associated with life-long dietary practices, these findings provide important insights for individuals working with young children.

Accepted for Publication: May 4, 2018.

Corresponding Author: Emily M. Melnick, MPH, Department of Health and Behavioral Sciences, University of Colorado Denver, Campus Box 188, PO Box 173364, Denver, CO 80217 (emily.melnick@ucdenver.edu).

Published Online: August 6, 2018. doi:10.1001/jamapediatrics.2018.1915

Author Contributions: Ms Melnick had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Concept and design: Both authors.

Acquisition, analysis, or interpretation of data: Melnick.

Drafting of the manuscript: Melnick.

Critical revision of the manuscript for important intellectual content: Both authors.

Statistical analysis: Melnick.

Obtained funding: Melnick.

Administrative, technical, or material support: Melnick.

Supervision: Li.

Conflict of Interest Disclosures: None reported.

Funding/Support: This work was supported by a grant from the Department of Health and Behavioral Sciences at the University of Colorado Denver (Ms Melnick) and grant 6471 from the Colorado Health Foundation to fund the Culture of Wellness in Preschools Program.

Role of the Funder/Sponsor: The sponsors had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.

Additional Contributions: We thank staff members within the Rocky Mountain Prevention Research Center at the Colorado School of Public Health, including Jini Puma, PhD; Karen Thomas, MPH; Jamie Powers, MPH; Deanna LaFlamme, MA; Jennie Quinlan, MPH; Charlotte Farewell, MPH; Joanna Coleman, MA; Nichelle Ortiz; and Tracy Doig, MEd. We also thank graduate research assistants at the University of Colorado Denver for their contributions to data collection, including Marisa Westbrook, MPH; and Shawna Guttman, MS, RD. They did not receive additional compensation for their contributions.