Emoticon use Increases Plain Milk and Vegetable Purchase in a School Cafeteria without Adversely Affecting Total Milk Purchase

Purpose: Choosing poor-quality foods in school cafeterias is a risk factor for childhood obesity. Given the option, children often select chocolate milk over plain white milk. Efforts to increase plain white milk selection, such as banning chocolate milk in school cafeterias, increases plain white fat-free milk (PWFFM) purchase but decreases the overall milk purchase. The purpose of this study was to determine whether emoticon placement next to healthful foods would increase healthful purchases, particularly PWFFM.

Methods: In an inner city elementary school with 297 children, "Green Smiley Face" emoticons were placed to encourage the purchase of healthful foods including an entrée with whole grains, fruits, vegetables, and PWFFM. Purchase data were obtained from cash register receipts. Differences were analyzed by χ(2) Care and Statistical Process Control (SPC) and Graphical Methods.

Results: Only 7.4% of students selected white milk at baseline compared with 17.9% after the emoticons were placed (P < 0.0001). There was a decrease in chocolate milk purchase from 86.5% to 77.1% with the addition of the emoticons (P < 0.001). There was no significant difference in total milk purchase: 93.4% before the emoticons compared with 94.9% after. There was no significant change in the purchase of entrée or fruits. However, there was, a significant increase in vegetable purchase from 0.70 vegetables purchased per student per day to 0.90 by SPC (>8 points above the mean).

Implications: The addition of emoticons increases the purchase of PWFFM and vegetables in a school cafeteria setting without adversely affecting total milk sales. Emoticons offer a practical, low-cost means to improve food selection by children.