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At a Glance


U.S. Department of Agriculture, Food and Nutrition Service

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School Nutrition Dietary Assessment Study-III

Guaranteeing that low-income children have enough to eat and consume the right mix of nutritious foods is a national policy concern. The National School Lunch Program (NSLP) and the School Breakfast Program (SBP) provide meals to children in about 95 percent of public schools, and many private schools across the nation. In 2007, the NSLP and SBP served, respectively, 30.5 million and 10.1 million children on an average day.

Mathematica collected data in 2005 for the third School Nutrition Dietary Assessment Study (SNDA-III) for the U.S. Department of Agriculture (USDA), Food and Nutrition Service. The study provided information on school meal programs, aspects of the school environment that affect the meal programs, nutrient content, and contributions of school meals to children's diets. The study also assessed the availability and consumption of competitive foods—foods that are sold in schools outside of the reimbursable meals.

Key Findings

School meals and competitive foods:

  • In school year 2004-2005, NSLP lunches offered and served by most schools met USDA goals for target nutrients over a typical week and were lower in saturated fat than meals offered and served in school year 1998-1999.
  • In school year 2004-2005, most schools offered and served SBP breakfasts that met USDA standards.
  • Foods sold in competition with USDA school meals were widely available on campus, particularly in secondary schools.

Students’ dietary intakes:

  • NSLP participants consumed more nutrients at lunch than nonparticipants.
  • Participants also were more likely than nonparticipants to have adequate usual daily intakes of key nutrients.
  • Breakfast intakes of SBP participants and nonparticipants were generally similar, as was the prevalence of inadequate usual daily intakes.
  • Competitive foods were consumed by fewer NSLP participants than nonparticipants. The most popular choices for both groups were energy dense and relatively low in nutrients.

A February 2009 supplement to the Journal of the American Dietetic Association presented findings from SNDA-III.

Data Collection Highlights

Mathematica is a recognized leader in collecting high quality nutrition data and analyzing complex food and nutrient data. We developed the sample design and recruited over 400 schools in 135 districts, collecting information on all foods served over a five-day period. Nutritional content was coded using a USDA nutritional database.

The study included six key data collection components: a menu survey of foods served under the NSLP and the SBP, 24-hour dietary recall interviews with school children, child and parent interviews, anthropometric measurements of school children, surveys of school district staff, and inventories of foods served a la carte in the school cafeteria. 

We interviewed school officials about the food service in their schools and the school environments. Trained interviewers collected 24-hour intake data from close to 2,500 children drawn from 300 of the schools. These in-person interviews used computer-assisted personal interviewing. Parents were interviewed to obtain household and contextual information.

Recruiting school districts was challenging because the study required a significant amount of staff time to complete the five-day menu survey and to facilitate parental consent. Participation at the district level was 83 percent for districts in the full sample and 79 percent for districts selected for student data collection. About 95 percent of schools completed the menu survey; 93 percent of schools selected for both school- and student-level data collection participated. 


Two articles by our obesity and nutrition researchers and based on data from our SNDA-III evaluation garnered the following honors:

“Association Between School Food Environment and Practices and Body Mass Index of US Public School Children” was selected by the Robert Wood Johnson Foundation as one of the top five articles that had a major policy impact in 2009. Read the press release.

"School Food Environments and Policies in US Public Schools," published in Pediatrics, was chosen by the Robert Wood Johnson Foundation as Most Influential Article of the Year in 2008.


Journal of the American Dietetic Association, Supplement (February 2009)
"School Nutrition Dietary Assessment Study-III: Summary of Findings" (November 2007)
"School Nutrition Dietary Assessment Study-III: Volume I: School Foodservice, School Food Environment, and Meals Offered and Served" (November 2007)
"School Nutrition Dietary Assessment Study-III: Volume II: Student Participation and Dietary Intakes" Appendices (November 2007)
"School Nutrition Dietary Assessment Study-III: Volume III: Sampling and Data Collection" (November 2007)