Study finds elementary school salad bars double fruit and vegetable intake
An ASU study found a significant increase in fruit and vegetable consumption among elementary-school children when salad bars are provided. Courtesy photo
In 1947, the National School Lunch Program was launched, offering free or reduced cost meals daily to nearly 30 million students nationwide. In 2010, the Healthy, Hunger-Free Kids Act was passed with the objective of increasing consumption of fruits, vegetables and whole grains.
In 2015, the Salad Bars in Schools Expansion Act was introduced in Congress to expand salad bars to more schools participating in the National School Lunch Program over five years. While the bill didn’t pass, it said that salad bars were effective at increasing fruit and vegetable consumption among elementary, middle and high school students. However, the research behind that conclusion did not show effectiveness in an experimental study.
That same year, two professors from Arizona State University received $2 million in grant funding from the National Heart, Lung, and Blood Institute within the National Institutes of Health to test whether salad bars were an effective strategy for increasing fruit and vegetable consumption.
Now, 10 years later, the data reveals an over 100% increase in elementary school fruit and vegetable consumption when salad bars are coupled with marketing strategies such as posters, table tents and announcements.
This research, which ran from 2017 to 2023 in elementary, middle and high schools across Arizona, furthers another study published in 2016, which revealed an increase in student consumption of fruits and vegetables when salad bars were placed inside the lunch line, rather than outside.
In the United States, most children fail to meet fruit and vegetable consumption recommendations, according to the U.S. Centers for Disease Control and Prevention. A balanced diet is critical to young children’s health, as well as their success in the classroom.
“(A balanced diet) helps with their growth, their academics. It helps establish healthy behaviors early in life, and we know that that leads to healthy behaviors in adulthood,” said Marc Adams, assistant dean of the School of Technology for Public Health and professor in the College of Health Solutions.
Adams led the study alongside former Health Solutions Associate Professor Meg Bruening. Among the other faculty members involved in the study is College of Health Solutions Director and Professor Punam Ohri-Vachaspati, whose research led to the Arizona Legislature providing free school meals for low-income students in public and charter schools.
“Increasing fruit and vegetable consumption among school-age children is critical for improving their diets and preventing chronic diseases down the line. This study provides clear evidence that salad bars in schools can go a long way in improving student consumption of fruits and vegetables, without adding any additional food waste,” Ohri-Vachaspati said.
“As we expand school meal access to more students, providing salad bars at school lunch can be an effective strategy for making these meals healthier.”
Adams’ six-year salad bar study measured fruit and vegetable intake over 10 weeks in elementary, middle and high schools statewide — from Yuma and Phoenix to Globe and Prescott. While data is still being processed for middle and high schools, elementary school results indicate a significant increase in fruit and vegetable consumption when salad bars are provided.
“By at least having them in place for 10 weeks, there's no novelty effect of just being introduced and kids are attracted to them, then they stop using them. We saw a meaningful increase in consumption that became stronger over 10 weeks. So I think that's strong evidence that it's not just a novel effect,” Adams explained.
Thirteen elementary schools with 50% of students eligible for free or reduced lunch participated in the study, none of which previously had salad bars. Across those schools, more than 3,000 children took part.
The study itself was four-pronged, looking at one control group and three other groups exploring the impact of salad bars and marketing each individually, then their effect together.
Fruit and vegetable items were measured twice before and after lunch. Using digital scales and photography, Adams’ team weighed students’ trays before and after their meal to check their fruit and vegetable intake.
“We took two measurements at the beginning, after they went through the service line, but before they ate, so we call that pre-lunch. Then photos after they ate. We intercepted them before they threw their lunch in the garbage. We put those trays aside, weighed and took photographs and laid them out of sight,” Adams said.
By comparing the two, the team was able to more accurately assess students’ fruit and vegetable intakes than if they had taken surveys. With this data, the researchers were certain that their results were significant.
Adams and his team found that introducing a salad bar led to an 87% increase in fruit and vegetable consumption in an elementary school environment. When paired with marketing strategies, fruit and vegetable consumption doubled.
“This study wasn’t about school salad bars. It was about how we best improve fruit and vegetable consumption for kids who have limited access to healthy foods," Bruening said. "We showed that salad bars, and especially with the addition of nutrition marketing, are really effective at increasing fruit and vegetable consumption. This is a relatively low-cost strategy that has large population health benefits.”
Increased nutrition reduces the risk of developing health conditions. Introducing salad bars in schools and making a balanced diet the easiest choice sets students up for a healthier, brighter future.
“If we can find small ways to improve consumption of fruits and vegetables among those 30 million students consuming lunch every day, that can have cumulative population-level benefits for them and for the communities that they live in,” Adams said.
“These kinds of studies are more than proof of concept. It is the confirmatory data that are needed to show that these types of strategies work and can be implemented system-wide.”
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