'Zero waste' approach to lunchroom recycling. Digital image. Waste360. N.p, 11 October 2017. Web.

How many students eat school lunch?
What do we know about food waste in schools?
Summary of findings
How do I conduct my own waste audit?
Summary of studies that examined all waste at schools
Summary of studies that examined plate waste at schools

How many students eat school lunch?

The number of students eating school lunch is only available for National School Lunch Program (NSLP) participants. We do not know how many students nationwide are buying lunch outside of the NSLP. We also cannot reasonably track food waste in schools from packed lunches without assessing all trash.

School lunches may be a significant source of food waste in America. United States Department of Agriculture (USDA) statistics show that 31 million students receive lunches each school day through the NSLP. An unknown number of students buy school lunches outside the NSLP.

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What do we know about food waste in schools?

Most school food waste figures discuss plate waste, which is how much a student puts on their plate but does not eat. Researchers collect this data because the NSLP uses tax dollars. Thus, the program is subject to both USDA evaluation and public scrutiny.

Studies increased after the Healthy, Hunger-Free Kids Act

Researchers collected more plate waste data after Michelle Obama's Healthy, Hunger-Free Kids Act. The studies measured plate waste in schools related to the law's new nutrition standards. However, the studies included a limited number of schools, and not all included data from prior years. Also, only one study examined the difference between the first and second year of the new nutrition standards. This article provides plate waste data but does not discuss what it means for the success or failure of nutrition standards.

Total school food waste in America remains largely unknown

Data is scarce on the quantity of school lunch that is prepared and then not served. Four studies give useful but limited information. Two of the studies looked at the amount of food waste in the total trash from the dining area. The two other studies looked at the amount of food waste in the total trash throughout the school.

One study in Florida compared food waste from three kitchens that each used different food preparation methods. This is the only study we have located that discusses the quantity of food that is prepared and then not served.

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Summary of findings

Below is a roundup of available school food waste information. Note that universities cooperated with private entities for two of the studies. Thus, biases benefiting the private organizations are possible.

Food waste by portion type

Letting students choose their food results in less waste. Schools that allowed students to choose what to put on their trays had less food waste.⁵
Middle schools waste fresh fruit the most. Middle school students wasted the following portions in order from most to least — fresh fruit, canned fruit, vegetables, milk, grains, entrées. Note that less than half chose a vegetable to begin with.⁶
Milk is wasted in highest numbers at elementary schools. Milk was the second most prevalent trash material in dining areas at elementary schools, making up 22.2% of the total waste.³
Vegetables have the greatest amount of waste variability in elementary schools. Preschoolers and kindergarteners showed the greatest waste variability for vegetables, wasting 26.1% on one day and 80.1% on another.¹¹
Vegetables are wasted more when served with a popular main course. More vegetables were wasted when paired with a popular entrée.⁸

Food waste by preparation and serving method

Food preparation training reduces plate waste. Cafeterias where workers were trained to make healthy school lunches more appetizing wasted less vegetables.⁷
More food is wasted overall when it is prepared in a school kitchen. Schools that prepared student meals in an onsite kitchen produced more food waste than schools that purchased pre-packaged meals or used caterers.³

Food waste in total trash

Food waste is the largest component of dining service area trash. Food waste made up more of the trash from a school's dining service area than any other material, ranging from 51.3%³ to 63%. ¹
Food waste is the largest component of total school trash. Food waste made up more of a school's trash than any other material, ranging from 23.9%² to 50.8%.⁴

Total plate waste data

Food waste increases before decreasing after new nutrition standards. Students produced more food waste in the first year following the Healthy, Hunger-Free Kids Act⁸ ⁹ ¹⁰, but less in the second year.¹⁰
Over a quarter of the food budget is wasted. The proportion of the food budget thrown away as plate waste was 26.1%.⁷ For preschoolers and kindergarteners, an average of $0.97 per plate was wasted. ¹¹
Preschool and kindergarten students waste almost half their food. On average, preschool and kindergarten students wasted 45.3% of all food and beverages from their plates.¹¹
Up to half of calories are wasted. Students wasted between 12%⁵ and 50%⁷ of calories from their plates.

Variability in food waste

Elementary schools vary on which portion they waste the most. In one study, elementary school students wasted grains the most, but less than half chose a vegetable to begin with.⁶ In another study, preschool and kindergarten classes wasted vegetables the most, but in this case each student had vegetables on their tray.¹¹
Variability in food waste is highest at elementary schools. Elementary schools had the greatest daily variability in food waste, ranging from about 20 to about 40 kilograms total for the whole school.³
Younger students and adolescent females waste the most food. Younger students and adolescent females produced more food waste in schools than older students and adolescent males, respectively.⁵

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How do I conduct my own waste audit?

Knowing how much waste your school produces is an important first step in the environmental planning process. You can use the documents below to plan a waste audit for the whole school or just the dining areas. Future articles on this website will discuss methods to reduce food waste in schools.

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Summary of studies that examined all waste at schools

The studies discussed below evaluated the quantity of food waste in total trash. The Minnesota and California studies looked at trash from the entire school, while the studies in Louisiana and Florida looked at trash only from the dining service areas. None of these studies specifically assessed plate waste.

1. Kansas State University Study (Collaboration)

Collection Year(s)	1995*
School(s) Location	Louisiana, Ascension Parish School District
School Type	2 elementary (K-4), 2 middle (5-8), and 3 primary (K-8) schools
Data Collection Method	Collected 20 days' worth of all waste in food service operations and separated them into the following categories — food, milk, and packaging
Findings	The largest trash material by weight was food waste at 63% of the total

Collaboration between Kansas State University, Louisiana State University, and the Ascension Parish School Board in Louisiana

Source — Kansas State University / Louisiana State University / Ascension Parish School Board Food Service Waste Analysis

*The study does not specifically state when the data was collected, but the research was published in 1995.

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2. Minnesota Pollution Control Agency Study

Collection Year(s)	2010
School(s) Location	Minnesota, Hennepin County and City of Minneapolis
School Type	2 elementary, 2 middle, and 2 high schools
Data Collection Method	Collected and sorted 2 days' worth of all waste (trash, recycling, and compost) throughout the school
Findings	The largest trash material was food waste at 23.9% of the total

Source — Minnesota Pollution Control Agency School Waste Analysis

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3. University of Florida

Collection Year(s)	2012
School(s) Location	Alachua County, Florida
School Type	1 public elementary, 1 public technical high, and 1 private middle/high school Schools with different food preparation methods were selected: Method A — Kitchen receives most foods pre-prepared or pre-packaged (public elementary school) Method B — Kitchen prepares all food (public technical high school) Method C — School does not have a kitchen, food is brought in by a caterer (private middle/high school)
Data Collection Method	Collected and sorted one week's worth of trash from food service areas
Findings	The elementary school showed the greatest daily variability in food waste, ranging from about 20 to about 40 kilograms total for the whole school The largest proportion of trash material in dining areas was food waste, with an average of 47.1% at the public elementary, 57.8% at the public technical high, and 48.9% at the private middle/high Milk was the second most prevalent trash material in dining areas at the elementary school, making up 22.2% of the total waste The kitchen that prepared all student meals produced the most food waste at 57.8% of the total, almost 10% higher than the average of the other two schools

Source — University of Florida School Food Waste Analysis

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4. California Department of Resources Recycling and Recovery Study

Collection Year(s)	2014
School(s) Location	California
School Type	Unknown*
Data Collection Method	Collected and sorted 45 waste samples*
Findings	The most prevalent material was organics, including food waste, at 50.8% of the total trash

Source — California Department of Resources Recycling and Recovery School Waste Analysis

*We located a summary of the findings, but not the full report denoting the school locations and data collection method.

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Summary of studies that examined plate waste at schools

The studies discussed below evaluated plate waste alone and did not examine how much food was prepared but not served. Four of the studies assessed waste related to the Healthy, Hunger-Free Kids Act. However, we present the data only as sources of school food waste in general.

5. USDA Study

Collection Year(s)	1991-1992*
School(s) Location	Nationwide, 45 states participated
School Type	Mixture of elementary, middle, and high schools (626 total) 568 public, 35 Catholic, and 23 private schools
Data Collection Method	Researchers conducted in-person interviews with the student or the parent. In part, they asked how much school lunch food the interviewee threw away.
Findings	On average, 12% of calories were wasted Younger students and adolescent females produced more food waste than older students and adolescent males, respectively Students at schools that allowed them to choose what to put on their tray had less food waste

Source — USDA School Nutrition Dietary Assessment Study-I

*The USDA conducts recurring studies on NSLP meal nutrition. To date, four such studies have been completed but only the first (completed 1991-1992) looked at plate waste.

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6. Colorado State University Study

Collection Year(s)	2010
School(s) Location	Northern Colorado
School Type	3 elementary and 2 middle schools
Data Collection Method	Participants were randomly selected 5 servings of each school lunch portion were photographed and weighed for reference Participants' trays were photographed before and after consumption About 20% of post-consumption portions were weighed to determine food waste
Findings	Elementary schools wasted 44.6% of grains, 37.3% of canned fruit, 37% of fresh fruit, 33.6% of vegetables, 32.6% of milk, and 23.8% of entrées Middle schools wasted 37.6% of canned fruit, 47.4% of fresh fruit, 30.6% of vegetables, 21.2% of milk, 20% of grains, and 19.2% of entrées Less than half chose a vegetable About 75% chose a fruit

Source — Colorado State University Plate Waste Analysis

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7. Harvard School of Public Health Study (Collaboration)

Collection Year(s)	2010-2011
School(s) Location	Boston, low-income and urban areas
School Type	4 middle schools 2 Chef Initiative (ChI) schools (professional chef, trained staff) 2 control schools
Data Collection Method	Days when each school had a similar menu were selected Random samples of school lunch portions were weighed Trays had unique identifying numbers, with a researcher recording what was on the tray Trays were weighed at the end of the meal to determine food waste
Findings	Cost of food discarded annually estimated to be $432,349 (26.1% of food budget); if translated nationally, this is $1,238,846,400 On average, students consumed about half of the calories served Students at ChI schools wasted less vegetables

Collaboration between Harvard School of Public Health, Project Bread, Children's Hospital Boston, Harvard Medical School, Brigham and Women's Hospital, and Tufts University

Source — Harvard School of Public Health Plate Waste Analysis

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8. Texas A&M University Study (Collaboration)

Collection Year(s)	April and May 2012 (Phase I — before Healthy, Hunger-Free Kids Act) and October and November 2012 (Phase II — after Healthy, Hunger-Free Kids Act)
School(s) Location	Central Texas
School Type	3 elementary schools
Data Collection Method	5 to 10 samples of each school lunch portion were weighed and averaged Separate trash bins were provided for each portion type Bins were weighed at the end of each school lunch period Only plate waste from entrées and vegetables was measured
Findings	Prior to the new standards, students wasted 28.6% of entrées and 52.1% of vegetables After new standards, students wasted 29.3% of entrées and 57.7% of vegetables Students wasted more vegetables when paired with popular entrées

Collaboration between Texas A&M University and Alliance for Potato Research and Education

Source — Texas A&M University Plate Waste Analysis

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9. University of Vermont Burlington Study (Collaboration)

Collection Year(s)	Spring 2012 (before Healthy, Hunger-Free Kids Act) and Spring 2013 (after Healthy, Hunger-Free Kids Act)
School(s) Location	Northeast United States
School Type	2 elementary schools
Data Collection Method	Fruit and vegetable portions were weighed and converted to cups Photographs were taken of students' trays when they left the school lunch line Only plate waste from fruits and vegetables were measured
Findings	Prior to the new standards, 15.7% of students did not place any fruits or vegetables on their trays After the new standards, 2.5% of students did not place any fruits or vegetables on their trays After the new standards, students threw away more fruits and vegetables from their plates

Collaboration between University of Vermont Burlington and University of California

Source — University of Vermont Burlington Plate Waste Analysis

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10. Yale University Study (Collaboration)

Collection Year(s)	2012 (before Healthy, Hunger-Free Kids Act) and 2013-2014 (after Healthy, Hunger-Free Kids Act)
School(s) Location	Urban, low-income district (exact location unspecified)
School Type	12 middle schools
Data Collection Method	3 servings of each school lunch item were weighed and averaged Pictures of students' trays were taken After lunch, each tray component was weighed to determine food waste
Findings	In 2012, students wasted 27.7% of fruit, 54.5% of vegetables, 29.1% of entrées, and 46.2% of milk In 2013, students wasted 39.3% of fruit, 61.1% of vegetables, 32.1% of entrées, and 46.4% of milk In 2014, students wasted 25.7% of fruit, 36.4% of vegetables, 16.4% of entrées, and 43.3% of milk

Collaboration between University of Connecticut, Henderson Consulting, University of California Berkeley, and Yale University

Source — University of California Berkeley / University of Connecticut / Yale University Plate Waste Analysis

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11. Montana State University Study (Collaboration)

Collection Year(s)	March 2013 (after Healthy, Hunger-Free Kids Act)
School(s) Location	Not identified, but is presumably Montgomery County, Virginia based on the author list for this study
School Type	1 elementary school (looked at 1 pre-kindergarten and 5 kindergarten classes)
Data Collection Method	Each food item was standardized and weighed prior to being served (study lasted for a week) Observation checklist and photographs were used to record which items were served to each student After lunch, each uneaten food item was deposited into a separate bin and weighed
Findings	On average, 45.3% (totaling 141.2 pounds) of all food and beverages from students' plates were wasted On average, students wasted 51.4% of vegetables, 51% of entrées, 45.5% of milk, and 33% of fruit Vegetables had the greatest variability in amount wasted, with 26.1% wasted on one day and 80.1% wasted on another Plate waste amounted to a $0.97 loss per meal served

Collaboration between Montana State University, Virginia Tech University, and Montgomery County Public Schools

Source — Montana State University / Montgomery County Public Schools / Virginia Tech University Plate Waste Analysis

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Food waste in American schools: how much is out there?

How many students eat school lunch?

What do we know about food waste in schools?

Studies increased after the Healthy, Hunger-Free Kids Act

Total school food waste in America remains largely unknown

Summary of findings

Food waste by portion type

Food waste by preparation and serving method

Food waste in total trash

Total plate waste data

Variability in food waste

How do I conduct my own waste audit?

Summary of studies that examined all waste at schools

1. Kansas State University Study (Collaboration)

2. Minnesota Pollution Control Agency Study

3. University of Florida

4. California Department of Resources Recycling and Recovery Study

Summary of studies that examined plate waste at schools

5. USDA Study

6. Colorado State University Study

7. Harvard School of Public Health Study (Collaboration)

8. Texas A&M University Study (Collaboration)

9. University of Vermont Burlington Study (Collaboration)

10. Yale University Study (Collaboration)

11. Montana State University Study (Collaboration)