School Lunches Show Modest Diet Gains, but Menu Cost May Shape Child Nutrition

For decades, public health researchers have pinned considerable hope on the school cafeteria as a lever for improving childhood nutrition. The logic is intuitive: if children eat a supervised, nutritionally planned meal at school, their overall diets and health should improve. But a new cross-sectional study from Spain, published in Pediatric Research, offers a more nuanced and, in some ways, surprising picture. A team led by María del Mar Uclés-Torrente and Gema Esperanza Ruiz-Gamarra of the University of Cordoba and the Maimonides Institute of Biomedical Research in Cordoba found that children who regularly ate in the school cafeteria did show slightly better adherence to the Mediterranean diet than their peers who ate at home, yet the two groups were largely indistinguishable on the anthropometric and cardiovascular measures that matter most to clinicians. The most striking signals in the study, in fact, had little to do with cafeteria attendance itself and everything to do with money and school type.

The research involved 171 school-aged children drawn from five primary schools in Spain, assessed between January and March 2025. The design was deliberately comprehensive. Each child underwent standardized anthropometric assessment following the International Standards for Anthropometric Assessment, including weight, height, and calculation of BMI-for-age z-scores referenced against World Health Organization growth data and CDC growth charts. Blood pressure was measured and interpreted according to the fourth report of the National High Blood Pressure Education Program Working Group, the reference standard for pediatric hypertension screening. Dietary quality was captured with the KIDMED index, a sixteen-point instrument developed by Serra-Majem and colleagues that scores adherence to the Mediterranean dietary pattern, long considered the gold-standard model of healthy eating in the region. Parents and children also reported dietary intake, which the researchers converted into percentages of recommended energy and nutrient targets using the Spanish food composition database BEDCA and European Food Safety Authority dietary reference values.

On the headline question, the results were mixed but informative. Children attending the school cafeteria scored a mean of 5.55 points on the KIDMED Mediterranean diet index, compared with 4.80 among non-attendees, with standard deviations of 3.32 and 3.69 respectively. That difference, while directionally favorable to the cafeteria group, was modest in absolute terms and sits against a sobering backdrop: both scores fall well below what would indicate strong adherence to a dietary pattern associated with lower cardiovascular and metabolic risk. Recent meta-analyses of Spanish youth have documented a worrying decline in Mediterranean diet adherence, and this study’s numbers, hovering near the middle of the scale, are consistent with that national trend. In other words, the cafeteria may nudge children in the right direction, but neither group of children is eating particularly well by the standards of the traditional Mediterranean pattern.

Perhaps the most counterintuitive finding concerns what the children who ate at home were actually consuming. Non-attendees reported higher energy intake, at 108.3 percent of recommended levels compared with 94.4 percent for cafeteria users, and markedly higher lipid intake, at 128.5 percent of recommendations versus 105.9 percent, a difference that reached statistical significance with a p-value of 0.006. The home-fed group also reported higher intakes of several micronutrients, with differences significant at p below 0.05. The authors interpret this pattern as suggestive of a more energy-dense dietary profile among children eating at home, one that delivers abundant calories and fat alongside certain micronutrients. That combination is precisely the signature epidemiologists associate with the modern obesogenic diet: plentiful energy and fat, often from processed and palatable foods, rather than the balanced, lower-energy-density pattern the Mediterranean model prescribes.

Yet when the researchers turned to the physical measurements, the expected differences largely failed to materialize. BMI-for-age z-scores and blood pressure did not differ significantly between cafeteria attendees and non-attendees, with p-values above 0.05. The one anthropometric exception was weight percentile, which did differ significantly between the groups at p below 0.001, though the cross-sectional design of the study makes it impossible to determine whether cafeteria attendance influenced weight, whether families with children of different weights choose cafeteria use differently, or whether some third factor, such as household income or parental work schedules, drives both. This is the fundamental limitation of cross-sectional evidence: it captures a snapshot, not a causal pathway, and self-selection into school meal programs is well documented in the international literature.

Where the study truly broke new ground was in its analysis of the school menus themselves, and specifically their cost. The researchers assessed the nutritional composition of the menus on offer and the daily cost per child, then tested whether these variables related to children’s intake and health indicators. The results were emphatic. Menu cost and school type, whether public, state-funded private, or fully private, were significantly associated with nutrient intake, anthropometric percentiles, and Mediterranean diet adherence, all at p below 0.001. In plain terms, the price tag attached to a school’s lunch program appeared to travel through the food on the plate and into the bodies and health markers of the children eating it. This is a socioeconomic gradient rendered in nutrients and percentiles, and it echoes a growing body of European and global evidence that school food quality varies systematically with the resources behind it.

The implications of that finding reach well beyond Spain. A 2026 review of school meal quality across twenty-nine countries published in Public Health Nutrition documented wide international variation in what schools actually serve, and a 2025 scoping review in Obesity Reviews found that affordability was a recurring fault line in European school food policy. Spain itself has made childhood obesity a national priority, with a strategic plan running from 2022 to 2030 and the long-standing NAOS strategy on nutrition, physical activity, and obesity prevention. The ALADINO 2023 national survey continues to document substantial rates of childhood overweight and obesity, with socioeconomic status among the strongest predictors. Against that backdrop, the Cordoba team’s suggestion that minimum per-child spending on school menus might need to be standardized is a policy proposal with real teeth, because it targets the resource gap that their data suggest is shaping what children eat.

The international evidence on school meals more broadly supports the idea that these programs can be powerful equity tools, particularly for food-insecure children. Systematic reviews of universal free school meal policies in the United States, including a 2024 review in JAMA Network Open and a 2021 synthesis in Nutrients, have found benefits for diet quality, food security, and school participation, with more limited and inconsistent effects on body mass index. Studies of the Healthy, Hunger-Free Kids Act published in JAMA in 2020 showed measurable improvements in dietary quality among participants in the US National School Lunch Program. Reviews spanning low- and middle-income countries have documented benefits for both educational and health outcomes. The Spanish study fits neatly into this literature: it finds dietary signals consistent with benefit, no dramatic anthropometric effects, and a strong suggestion that the quality of what is served, not merely whether it is served, determines the outcome.

Several caveats deserve emphasis before the findings are translated into policy. The sample of 171 children from five schools is small and geographically concentrated, and the cross-sectional design cannot establish that cafeteria meals caused the observed differences in diet quality or weight percentiles. Dietary intake data relied on reported consumption, a method inherently vulnerable to recall and social desirability bias, particularly in children. The KIDMED index, while widely used, is a screening tool rather than a full dietary assessment. And the significant differences in micronutrient intakes favoring the home-fed group complicate any simple narrative that cafeteria eating is uniformly healthier; the pattern more likely reflects overall dietary volume and composition than the cafeteria meal itself. Longitudinal and intervention studies, ideally with objective dietary measures and sufficient power to detect changes in growth trajectories, would be needed to confirm causal pathways.

Even with those limitations, the study lands at a consequential moment. Global analyses from the NCD Risk Factor Collaboration published in The Lancet in 2024 documented that more than 370 million children and adolescents worldwide now live with obesity, a figure that has risen relentlessly since 1990, and pediatric obesity is firmly linked to long-term cardiovascular, metabolic, and psychological consequences. School food environments remain one of the few settings where nearly all children, regardless of family circumstances, can be reached daily. The Spanish findings refine the message for policymakers: simply having a cafeteria is not enough, and the modest dietary advantage observed among attendees suggests that well-designed school meals can gently steer children toward better patterns. But the strong associations between menu cost, school type, and nearly every nutritional outcome measured indicate that the deeper variable is investment. If school meals are to function as an equity instrument, the authors’ case for guaranteeing a minimum standard of per-child spending may prove to be the study’s most important contribution.

Subject of Research: Associations between school cafeteria attendance, dietary intake, and nutritional status in Spanish primary school children

Article Title: Associations between school meal attendance, dietary intake and nutritional status in Spanish school-aged children: a cross-sectional study

Article References: Uclés-Torrente, M. D. M., Ruiz-Gamarra, G. E., Alcalde-Llergo, J. M., Vaquero-Álvarez, M., Blancas-Sánchez, I. M., Aparicio-Martínez, P., & Vaquero Abellán, M. (2026). Associations between school meal attendance, dietary intake and nutritional status in Spanish school-aged children: a cross-sectional study. Pediatric Research. https://doi.org/10.1038/s41390-026-05442-1

Image Credits: AI Generated

DOI: 10.1038/s41390-026-05442-1

Keywords: school meals, childhood obesity, Mediterranean diet, pediatric nutrition, school cafeteria, dietary intake, nutritional status, menu cost, socioeconomic gradient, KIDMED index, Spain, public health