Student Acceptance of Plain Milk Increases Significantly 2 Years after Flavored Milk Is Removed from School Cafeterias: An Observational Study

Abstract

Background: Previous studies document decreases in lunchtime milk consumption immediately after flavored milk is removed. Less is known about longer-term effects.

Objective: Plain milk selection and consumption were measured the first year flavored milk was removed in a school district (2010 to 2011 [Time 1]) and 2 years later (2012 to 2013 [Time 2]). Four behavioral economic interventions to promote milk were tested in one school at Time 2.

Design: This was a longitudinal, observational study.

Participants/setting: Participants were kindergarten through grade 8 students in two schools in an urban district. Primary data were collected 10 times per school year at Time 1 and Time 2, yielding 40 days of data and 13,883 student observations. The milk promotion interventions were tested on 6 additional days.

Main outcome measures: Outcomes were the percentage of students selecting milk at lunch, the ounces of milk consumed per carton, and the ounces of milk consumed school-wide per student.

Statistical analyses: Logistic regressions were used to assess how sex, grade, time, availability of 100% juice, and behavioral interventions affected milk selection and consumption.

Results: At Time One, 51.5% of students selected milk and drank 4 oz (standard deviation=3.2 oz) per carton, indicating school-wide per-student consumption of 2.1 oz (standard deviation=3.0 oz). At Time Two, 72% of students selected milk and consumed 3.4 oz per carton (standard deviation=3.2 oz), significantly increasing the school-wide per-student consumption to 2.5 oz (standard deviation=3.1 oz). Older students and boys consumed significantly more milk. Availability of 100% fruit juice was associated with a 16-percentage point decrease in milk selection. None of the behavioral economic interventions significantly influenced selection.

Conclusions: These data suggest that after flavored milk is removed from school cafeterias, school-wide per-student consumption of plain milk increases over time. In addition, the presence of 100% juice is associated with lower milk selection.

Keywords: Juice; Milk; National School Lunch Program (NSLP).