Lunch Salad Bars in New Orleans' Middle and High Schools: Student Intake of Fruit and Vegetables

School Nutrition Environment and Services: Policies and Practices That Promote Healthy Eating Among K-12 Students

BACKGROUND

Changes to policies at the federal, state, and local levels over the last decade have influenced the school nutrition environment and services.

METHODS

This systematic review includes an analysis of individual research articles and government reports published from 2010 to 2021 that examine interventions to improve the school nutrition environment and services and increase the availability, selection, and consumption of healthier foods and beverages in K-12 schools in the United States.

RESULTS

Nutrition standards for school meals and food outside of meals improved access to healthier options in school. Providing school nutrition professionals with professional development, improving the palatability of school meals, offering taste tests, pre-slicing fruit, providing recess before lunch, offering incentives for trying healthier options, and providing access to drinking water resulted in increased selection and consumption of healthier items. There were inconclusive or mixed findings for some intervention strategies including adequate seat time for meals.

CONCLUSIONS

Despite demonstrated improvements to school meal programs and competitive foods, more work is needed to change the selection and consumption of healthier options among K-12 students. Schools can use multiple interventions to improve the school nutrition environment and services and help students adopt food and beverage choices that support health.

Design and rationale for evaluating the impact of salad bars on elementary school students' fruit, vegetable, and energy intake: a wait list control, cluster randomized controlled trial

BACKGROUND

Most children do not consume the recommended amount of fruit and vegetable (FV) servings. Changing the school food environment can be a cost-efficient, effective approach to improving children's dietary quality. There is great popular support for school salad bars as a means to increase children's FV intake within the National School Lunch Program (NSLP), yet empirical research is limited. Further, although FV consumption can facilitate healthy weight management if these foods replace high calorie items, there is a need to enhance understanding of salad bars' influence on children's diet quality and energy intake within the NSLP. This is particularly important to investigate in schools in communities characterized by high poverty, as students they serve are particularly likely to rely on school meals.

METHODS

This report describes the design and rationale of a federally-funded investigation that uses validated methods to evaluate school salad bars. This district plans to install salad bars into 141 elementary schools over 5-years, facilitating the conduct of a waitlist control, cluster randomized controlled trial. Specifically, 12 pairs of matched schools will be randomly selected: half receiving a salad bar (Intervention) and half serving pre-portioned FVs only, standard under the NSLP (Control). Thus, groups will have different FV presentation methods; however, all schools will operate under a policy requiring students to take at least one FV serving. Schools will be matched on Title I status and percent of racial/ethnic minoritized students. Intake will be objectively assessed at lunch in each school pair, prior to (baseline), and 4-6 weeks after salad bars are installed (post), yielding ~ 14,160 lunch observations throughout the study duration. Cafeteria sales and NSLP participation data will be obtained to determine how salad bars impact revenues. Finally, implementation factors and cafeteria personnel's perspectives will be assessed, to identify barriers and facilitators to salad bars use and inform sustainability efforts. Proposed methods and current status of this investigation due to COVID-19 are described.

DISCUSSION

Results will have great potential to inform school nutrition policies and programs designed to improve dietary quality and reduce obesity.

TRIAL REGISTRATION

Retrospectively registered (10/28/22) in clinicaltrials.gov (NCT05605483).

Strategies to Improve School Meal Consumption: A Systematic Review

School meals can play an integral role in improving children's diets and addressing health disparities. Initiatives and policies to increase consumption have the potential to ensure students benefit from the healthy school foods available. This systematic review evaluates studies examining initiatives, interventions, and policies to increase school meal consumption. Following PRISMA guidelines, this review was conducted using four databases and resulted in a total of 96 studies. The research evidence supports the following strategies to increase school meal consumption: (1) offering students more menu choices; (2) adapting recipes to improve the palatability and/or cultural appropriateness of foods; (3) providing pre-sliced fruits; (4) rewarding students who try fruits and vegetables; (5) enabling students to have sufficient time to eat with longer (~30 min) lunch periods; (6) having recess before lunch; and (7) limiting students' access to competitive foods during the school day. Research findings were mixed when examining the impact of nutrition education and/or offering taste tests to students, although multiple benefits for nutrition education outside the cafeteria were documented. There is some evidence that choice architecture (i.e., "Smarter Lunchroom") techniques increase the proportion of students who select targeted meal components; however, there is not evidence that these techniques alone increase consumption. There were limited studies of the impact of increasing portion sizes; serving vegetables before other meal components; and strengthening local district and/or school wellness policies, suggesting that further research is necessary. Additionally, longer-term studies are needed to understand the impact of policies that limit students' access to flavored milk. Several studies found increases in students' meal consumption following the Healthy Hunger-Free Kids Act (HHFKA) and concerns regarding an increase in food waste following the HHFKA were not supported. Overall, there are a range of effective strategies to increase school meal consumption that can be implemented by schools, districts, and policymakers at the local, state, and federal levels (PROSPERO registration: CRD42021244688).

Salad bars and energy intake in Virginia elementary schools with free meals

School salad bars are widely promoted as a means to increase adherence to National School Lunch Program (NSLP) nutrition mandates. Yet it is unknown how salad bars or fruit and vegetable (F&V) intake relates to energy intake within the NSLP, or if F&Vs displace energy from other sources. This relation is particularly important to understand among children from minoritized backgrounds, who are at high risk of obesity and food insecurity, and the most likely to be impacted by school food policies, given their reliance on school meals. This study purpose was to evaluate if school salad bars and F&V intake are associated with lower lunch energy intake. Energy intake in Virginia elementary schools with and without salad bars, and associations between F&V energy and other energy sources, were examined. Cross-sectional plate waste assessments were conducted in matched school pairs (3 with, 3 without salad bars; N = 1,102 students; >90% Black and Latinx; 100% free meals). Two-level hierarchical models assessed group differences in energy intake and the proportion of energy from each meal component. Mean total lunch energy intake was 304 ± 157 kcal (salad bar); 269 ± 152 kcal (no salad bar). Students in salad bar schools consumed more energy from vegetables (+11 kcal; P < .001). Energy intake patterns were inconsistent across pairs. F&V energy was not associated with non-F&V energy (F = 1.04, P = .31). Findings do not suggest that salad bars were associated with lower energy intake. Evidence was inconsistent regarding F&V displacement of other lunch calories. Further research regarding F&V, salad bars, and energy intake is needed.

Diet Quality Is Lower for Those Who Skip Lunch Among a Sample of Predominantly Black Adolescents

PURPOSE

To compare the dietary quality among adolescents who skip lunch and those who do not and explore associations between school-level variables, demographic variables and lunch skipping.

DESIGN

Cross-sectional.

SETTING

Public schools in New Orleans, Louisiana (n = 21).

PARTICIPANTS

718 adolescents.

METHODS

Adolescents participated in a 24-hour dietary recall using the Automated Self-Administered 24-Hour (ASA24) Dietary Assessment Tool early in 2013. Data were converted into Healthy Eating Index (HEI-2010) scores. Mean scores were compared between students who skipped lunch and those who did not. A multilevel analysis was conducted to assess relationships between school environment, demographics, and lunch skipping.

RESULTS

Of the 718 respondents, 88.3% were Black and 15.3% skipped lunch. Students who ate lunch had a mean HEI score of 46.6 compared to a mean score of 41.7 for students who skipped lunch (p < .001). Students who skipped lunch also had significantly lower intake of total vegetables (p = .02), whole fruits (p < .001), total dairy (p = .003), total protein (p < .001).

CONCLUSIONS

Skipping lunch was associated with lower quality diet, though diet quality was low among all students. Considering over 15% of the sample did not eat lunch in a closed-campus school setting, further research should consider how to encourage students to participate in the National School Lunch Program, which has the ability to increase diet quality in adolescents.

Salad Bars and Fruit and Vegetable Intake in Title I Elementary Schools

Objective

Despite widespread support for salad bars as a means to increase fruit and vegetable (F&V) intake within the National School Lunch Program (NSLP), empirical support for their use is limited. This cross-sectional study examined associations between salad bar access and F&V selection and consumption in Title I elementary schools in Virginia serving universal free meals.

Methods

Three matched pairs of schools (3 with salad bars; 3 without [control]) were randomly selected. Digital imagery plate waste methods assessed F&V selection, waste, and consumption. N = 1559 trays (N = 760 salad bar; N = 799 control) from 1^st-5^th grade students were analyzed (92.5% NSLP participation; 98.6% racial/ethnic minority).

Results

Salad bar usage varied widely (8.2%-63.8%). Different patterns of F&V selection and consumption were observed across pairs. Vegetable selection was higher in one salad bar school (+43.6g; q < .001) and vegetable consumption higher in 2 salad bar schools (+15.3g [q = .005]; +8.3g [q = .022]), compared with matched controls. Students in 2 salad bar schools selected more fruit than controls (+30.2g and +18g; qs < .001), yet fruit consumption differed across all 3 pairs.

Conclusions

Salad bar access might facilitate children's vegetable intake. Inconsistent results across school pairs suggest that school food environment factors other than salad bar access influenced F&V consumption.

A systematic review of school meal nudge interventions to improve youth food behaviors

Background

School meal programs have a large reach and thus are ideal environments in which to implement interventions targeting improved youth eating behaviors and reduced food waste. This systematic review summarizes the evidence on the effectiveness of school meal nudge interventions on influencing children’s eating and waste behaviors.

Methods

Inclusion criteria required studies have participants in primary or secondary school (grades K-12) with interventions that occurred during school lunch or breakfast in the cafeteria and included at least one of the following outcomes: selection, consumption, waste, or school meal participation. Analyses of intervention outcomes were restricted to studies of strong and moderate quality.

Results

Twenty-nine studies were included in the quality assessment. Included interventions fell into three categories: 1) placement/convenience, 2) marketing/promotion, or 3) variety/portions. The 20 strong and moderate quality studies included in outcome analyses generally used strong data collection methods and study designs, but were limited by an overall lack of intervention fidelity checks. Multi-component interventions often did not use methods that allowed for separate analyses of outcomes for different intervention components.

Conclusions

School meal nudge interventions were positively associated with food selection, and had an inconsistent relationship with food consumption. There were few studies evaluating the impact of nudge interventions on meal participation or food waste. The limited evidence available links nudges to improved meal participation, as well as undesirable increases in food waste. Future research in this area should use methods that incorporate implementation metrics, attend to systems factors, and allow the outcomes of individual intervention components to be isolated.

Comparisons of school and home-packed lunches for fruit and vegetable dietary behaviours among school-aged youths

OBJECTIVE

School-based interventions and policies encourage youths to include and consume fruits and vegetables at lunchtime via school lunches, but limited research has examined how these behaviours compare when youths have home-packed lunches. The objective of the present study was to compare fruit and vegetable contents and consumption among students having school or home-packed lunches over the school week.

DESIGN

Participants were observed over five consecutive days at school lunchtime. Trained analysts estimated students' lunchtime fruit and vegetable contents and consumption using digital imaging. Mixed models examined associations between fruit and vegetable dietary behaviours and lunch source (school v. home-packed), controlling for student gender, grade and school.

SETTING

Three elementary schools in northern California, USA.ParticipantsFourth-, fifth- and sixth-grade students (nchildren 315; nobservations 1421).

RESULTS

Students were significantly less likely to have and to consume fruits and vegetables (all P&lt;0·05) when having home-packed lunches, compared with when having school lunches. Among those who did have or did consume these foods, having a home-packed lunch was associated with consuming significantly less fruit (P&lt;0·05) but no differences for other dietary outcomes.

CONCLUSIONS

The study adds to a growing body of literature indicating shortfalls in fruit and vegetable contents and consumption associated with having a home-packed lunch, relative to having a school lunch. Findings suggest that school-based interventions, particularly when targeting home-packed lunches, should focus on whether or not these foods are included and consumed, with less emphasis on quantities.

Design and rationale for evaluating salad bars and students' fruit and vegetable consumption: A cluster randomized factorial trial with objective assessments

Building healthy fruit and vegetable (FV) consumption habits early in life is critical for primary prevention. However, U.S. youth do not come close to meeting national recommendations for FV intake. School-lunch salad bars are one of the most heavily promoted ways to meet FV guidelines. Contrary to popular belief, no rigorous randomized trials have examined whether salad bars increase students' FV consumption. This paper describes the design and rationale of a federally funded trial to evaluate whether introducing salad bars in elementary, middle, and high schools affects students' FV consumption and waste during lunch. A cluster factorial randomized trial will test new salad bars against waitlist controls, with and without an additional marketing intervention (N = 36 schools, N = 6804 students: n = 12 elementary, n = 12 middle and n = 12 high schools). Objective plate waste measurements of individual student's selection of FVs, consumption, and waste will be conducted using digital scales. Primary aim includes comparing FV consumption in schools without salad bars to those with new salad bars by grade level. Secondary aims include: a) whether FV marketing impacts the success of salad bars for FV consumption; b) whether salad bars differentially result in more FV waste compared to traditional serving methods; c) cost-benefit of using salad bars for consumption over traditional serving methods. When complete, this study stands to be one of the most definitive on the effectiveness of salad bars and contextual factors impacting their success. Findings will provide evidence for how to best spend limited federal dollars to improve FV intake in schools. Trial registration: ClinicalTrials.gov Identifier: NCT03283033 (date of registration: 9/14/2017).

Salad Bars Increased Selection and Decreased Consumption of Fruits and Vegetables 1 Month After Installation in Title I Elementary Schools: A Plate Waste Study

OBJECTIVE

To evaluate the 1-month impact of salad bars on fruit and vegetable (FV) selection, intake, and waste.

DESIGN

Pre-post quasi-experimental design.

SETTING

Title I elementary schools in a large, urban district in central Virginia.

PARTICIPANTS

Students (grades 1-5; >95% African American) from 2 elementary schools participated in plate waste assessments (282 plates were rated at baseline, 443 at post-assessment); fourth- and fifth-grade students from 15 (of 18 eligible) schools (n = 1,193) responded to surveys.

INTERVENTION

Digital imagery plate waste assessments were conducted before salad bars were installed (baseline) and 1 month afterward (post). Post-surveys examined student perceptions of salad bars.

MAIN OUTCOME MEASURES

Fruit and vegetable selection, consumption, and waste.

ANALYSIS

General linear models (without considering clustering) examined changes in outcomes, controlling for school. Frequencies and qualitative analyses were applied to survey data.

RESULTS

At post, students selected more types of FVs (1.81-2.58; P < .001), although FV consumption decreased by 0.65 cups (P < .001). Given the smaller portions selected, there was less FV waste (0.27 cups; P < .001) at post. Students liked the ability to choose FV from salad bars.

CONCLUSIONS AND IMPLICATIONS

Short-term exposure to salad bars increased the number of FV students chose but decreased FV consumption. Additional strategies are needed to increase FV consumption.

Reliability and Validity of Digital Imagery Methodology for Measuring Starting Portions and Plate Waste from School Salad Bars

BACKGROUND

Scientifically sound methods for investigating dietary consumption patterns from self-serve salad bars are needed to inform school policies and programs.

OBJECTIVE

To examine the reliability and validity of digital imagery for determining starting portions and plate waste of self-serve salad bar vegetables (which have variable starting portions) compared with manual weights.

DESIGN/METHODS

In a laboratory setting, 30 mock salads with 73 vegetables were made, and consumption was simulated. Each component (initial and removed portion) was weighed; photographs of weighed reference portions and pre- and post-consumption mock salads were taken. Seven trained independent raters visually assessed images to estimate starting portions to the nearest ¼ cup and percentage consumed in 20% increments. These values were converted to grams for comparison with weighed values.

STATISTICAL ANALYSES

Intraclass correlations between weighed and digital imagery-assessed portions and plate waste were used to assess interrater reliability and validity. Pearson's correlations between weights and digital imagery assessments were also examined. Paired samples t tests were used to evaluate mean differences (in grams) between digital imagery-assessed portions and measured weights.

RESULTS

Interrater reliabilities were excellent for starting portions and plate waste with digital imagery. For accuracy, intraclass correlations were moderate, with lower accuracy for determining starting portions of leafy greens compared with other vegetables. However, accuracy of digital imagery-assessed plate waste was excellent. Digital imagery assessments were not significantly different from measured weights for estimating overall vegetable starting portions or waste; however, digital imagery assessments slightly underestimated starting portions (by 3.5 g) and waste (by 2.1 g) of leafy greens.

CONCLUSIONS

This investigation provides preliminary support for use of digital imagery in estimating starting portions and plate waste from school salad bars. Results might inform methods used in empirical investigations of dietary intake in schools with self-serve salad bars.