Leftover School Lunch in Japan: Leftover Rates and Ways to Cut Waste

How Much School Lunch Is Left Over? A Look at the Numbers

School Lunch Is Part of Japan's Overall Food Loss

According to estimates by the Ministry of the Environment and the Ministry of Agriculture, Forestry and Fisheries, Japan's food loss in FY2023 was about 4.64 million tonnes: roughly 2.33 million tonnes from households and 2.31 million tonnes from business activities. That is about 80,000 tonnes less than the 4.72 million tonnes of FY2022, but a gap remains to the government's FY2030 targets (a 50% cut for households and a 60% cut for businesses, both from the FY2000 level).

School lunch is included in part of this business-related food loss. It runs on a system unlike homes or restaurants: a large number of meals prepared at once at a fixed time every day. That gives leftovers a pattern of their own. This article checks the reality of leftover school lunch against official survey figures, and considers why food is left over and how to reduce it, including the perspectives of local sourcing and fish-based school lunches.

What the “Leftover Rate” Measures

The figure most often used when discussing leftover school lunch is the leftover rate (zanshoku-ritsu). It is the share of food left uneaten relative to the amount prepared for the number of pupils present. For example, if rice for 100 people is prepared and the equivalent of 6 portions is left, the leftover rate for rice is 6%.

Note that the leftover rate varies greatly by dish and by day. Many schools and municipalities report that it is low on days with popular curry or fried food, and tends to be higher on days with soups, dressed salads and fish dishes. Looking only at a term-long average hides these day-to-day swings.

What the Ministry of the Environment Survey Shows

The Ministry of the Environment, with the cooperation of the Ministry of Education, Culture, Sports, Science and Technology (MEXT), surveyed municipal boards of education nationwide about food loss from school lunches and published the results. The survey was carried out in January 2015 with a response rate of about 80%. The main figures that can be read from it are shown below.

What stands out is that only about 30% of municipalities were tracking their leftover rate. If you do not measure, you cannot tell whether leftovers are shrinking or growing. The survey shows that the first step in reduction is to make leftovers visible.

Leftovers Are Not the Only “Loss” in School Lunch

Food waste from school lunches includes not only leftovers left by pupils, but also cooking scraps generated during preparation (vegetable peels and stems, fish bones and skin) and surplus from serving. In MEXT-related estimates, food loss in school lunches is said to be in the tens of thousands of tonnes a year, and leftovers are often described as accounting for roughly 40% of it. Looking at leftovers alone therefore shows only about half of the picture.

In the following chapters, we first look at why leftovers occur, then at losses in the cooking stage, local ingredients and fish-based menus, food education, and finally what families can do.

Why Is School Lunch Left Over? Five Reasons

Reason 1: Not Enough Time to Eat

In many schools, lunchtime including serving and cleaning up fits into about 40 minutes, and the time actually spent eating can be only half of that. For pupils who talk while eating or eat slowly, lack of time is the most direct cause of leftovers. Studies and municipal reports on leftover amounts also list securing enough time to eat as a factor that affects leftovers.

On days when time runs short, soups and side dishes often come back untouched. Pupils start with the staple and main dishes that require the most bites, and whatever is left for last becomes too much to finish.

Reason 2: Portions Do Not Match Appetite

School lunch portions are set according to nutritional standards for each grade. But even within one grade, there are large individual differences in build, activity level and condition on the day. Some pupils on sports teams want larger servings, while others have skipped breakfast, have no appetite or simply eat little. When everyone gets the same amount, some children inevitably get too much while others get too little.

Reason 3: Dislike of Taste, Texture or Smell

Foods children dislike are said to cluster around bitter vegetables, the smell and bones of fish, and distinctive textures such as hijiki seaweed and konnyaku. Taste preferences also change with experience, so leftovers rise when unfamiliar dishes appear or when an ingredient rarely served at home is on the menu.

Reason 4: Menu Combinations and Ease of Eating

Even the same ingredient can be easier or harder to eat depending on the cooking method, presentation and how much liquid there is. A grilled fish with bones, for example, is hard to eat and takes time to debone. A thick, chunky soup that is hard to scoop is another small factor that affects leftovers. Nutrition teachers, school dietitians and cooks work daily on such “ease of eating.”

Reason 5: Classroom Atmosphere and Attitude Toward Meals

Whether pupils were moving around before eating, whether the classroom is calm, and whether a teacher eats with them all affect leftovers. Some reports say that treating lunch not as a gap between lessons but as a time to learn about food changes how children approach meals.

Is Telling Pupils to “Finish Everything” Really Good?

There are also cautious views about strongly demanding that pupils “eat everything” for the sake of cutting food loss. For children who want to eat but cannot, who have allergies or are unwell, or who feel anxiety about eating, being forced to finish can be painful and can even make them dislike meals themselves.

In the approach to food education promoted by MEXT as well, the goal is not to “make children eat” but to foster gratitude for food and the ability to judge and eat an amount that suits oneself. Efforts to cut leftovers must always go hand in hand with protecting children's physical and mental health.

Where Losses Arise in School Lunch: Cooking, Serving and Recycling

Cooking Scraps: From Vegetable Peels to Fish Bones

School kitchens prepare meals for hundreds to more than a thousand people at once every day. Cooking scraps such as vegetable peels, stems and root ends, fish bones and skin, and eggshells tend to add up. Recently, many school lunch centers have introduced ways to use every part of an ingredient, such as turning daikon peels or broccoli stems into stir-fried side dishes or soup.

Much of the scrap can be reduced by not wasting the edible parts of ingredients. From the standpoint of hygiene, however, damaged parts and inedible parts cannot simply be used. A balance between using everything and keeping food safe is required.

Serving Losses: Absences, Events and Miscounted Quantities

School lunch is prepared for a headcount fixed in the morning. Absences, early departures, class closures and event-related changes on the day can leave prepared food over. Because quantities are hard to adjust once cooking has begun, how to handle surplus is a challenge.

For hygiene reasons, re-serving surplus lunch to pupils or letting them take it home is generally not permitted. This is an important rule to prevent food poisoning, and even when the purpose is to cut food loss, hygiene risks must take priority. Some municipalities have introduced ways to tell the kitchen about schedule changes early and to fine-tune ordering quantities.

Where Leftovers Go: Recycling and Disposal

In the Ministry of the Environment survey, the recycling rate of food waste from school lunches was about 59%, of which roughly 40% was turned into fertilizer (compost) and about 18% into animal feed. The rest is thought to be incinerated or otherwise disposed of. Some municipalities practise “food cycles” in which composted leftovers are used in school flower beds and local farmland, and the vegetables grown appear in school lunches again.

Recycling, however, is only the “exit” for food loss. Waste prevention (reduce), keeping leftovers and cooking scraps from arising in the first place, is the top priority. Under Japan's Food Recycling Act as well, the basic order for food waste is prevention first, then recycling (fertilizer, feed and so on), and heat recovery or volume reduction for whatever remains.

As seen at the start, even the overall estimates show millions of tonnes of food loss arising every year from both households and business activities. The current state of food loss in Japan can be checked on the Ministry of the Environment page on reducing food loss and food waste and on the Consumer Affairs Agency's page announcing the estimates. School lunch is only one site among them, but because it is where children experience leaving or not leaving food every day, it carries great educational significance.

Local Sourcing and School Lunch: Do Local Ingredients Change Leftovers?

The Current Use of Local and Domestic Ingredients in School Lunch

Using locally produced ingredients (jiba sanbutsu) and domestic ingredients in school lunch is promoted jointly by the Ministry of Agriculture, Forestry and Fisheries and MEXT. The Fourth Basic Plan for the Promotion of Shokuiku (food education) sets a target that at least 90% of prefectures maintain or improve their usage rate of local and domestic ingredients in school lunch (by value) from the FY2019 level. The FY2019 national averages by value were about 52.7% for local products and about 87% for domestic ingredients.

MEXT surveys this situation every year; the FY2022 survey covered five days in the third weeks of June and November 2022. The calculation of usage rates has also been changed from an ingredient-count basis to a value basis, which better reflects the efforts of producers and school lunch staff.

Local Products as “Living Teaching Material”

A guide to using local products in school lunches published by the Ministry of Agriculture, Forestry and Fisheries positions local products as “living teaching material” for food education. They are expected to deepen understanding of regional culture and industry, and, through contact with local producers, to nurture appreciation for producers' efforts and gratitude for food.

The ministry also publishes a guidebook for getting started (“Starting with Small Steps: Using Local Products in School Lunches”), case studies from 12 regions across Japan, and practical calculation tools. It is designed so that even schools and municipalities that find the barrier high can begin with something like “one day a month when local ingredients are used.”

Local Fish in School Lunch: An Example from Imabari, Ehime

In Imabari, Ehime Prefecture, the use of local fish has been increased since fiscal 2009 with the cooperation of the local fishery cooperative. By processing the fish into fillets and freezing them at a seafood processing plant, the city built a system that can supply large quantities, and it serves school lunches made with wild red sea bream (madai) to all elementary and junior high school pupils in the city about three times a year.

What this case shows is that the biggest hurdles to putting fish into school lunch are “quantity” and “processing,” and that the fishery cooperative, processors and kitchens solved them together. Preparing fish dishes for thousands of meals at once requires uniformly sized fillets, bone handling, frozen storage and hygiene management to all be in place.

Challenges: Hygiene, Specifications, Stable Supply and Time

Using local products has its challenges too. The Ministry of Agriculture, Forestry and Fisheries lists hygiene management, ingredient specifications, time limits on cooking and delivery, and stable production and supply of agricultural products as the main ones. Poor weather can mean no vegetables, and irregular shapes may not suit cooking machinery. Solving these requires working step by step, together with local producers and distributors, not only with education staff.

Using local products does not necessarily reduce leftovers. Still, many schools report that on days when ingredients come from producers whose faces are known, or fish from the local sea, children start asking “Which farm did these vegetables come from?” or “Which sea was this fish caught in?”, and their attitude toward food changes.

Fish in School Lunch: Overcoming the Barriers of Smell and Bones

Why Is Fish Often Left Over in School Lunch?

Fish is a nutritious food. In addition to high-quality protein, oily fish contain fats such as DHA and EPA, and fish provide calcium and vitamin D. On the other hand, it is said that fish dishes tend to be left over more often than meat dishes in school lunch. There are three main reasons.

• Smell: some children dislike the smell of cooked fish
• Bones: small bones make fish hard to eat and raise worries about choking
• Unfamiliarity: fish is eaten less often at home, so children are not used to the taste and texture

Household fish consumption is said to be declining in recent years, and in some areas school lunch is one of the few chances children have to meet fish. That is why both the meaning of serving fish and ways to make it easier to eat matter.

Cooking and Processing Ideas to Make Fish Easier to Eat

The Fish Eating Promotion Center run by the Japan Fisheries Association (Dainippon Suisankai) publishes fish recipes for school lunches, collecting practical information on handling bones, seasoning and cooking methods. Typical ideas are summarised below.

Effects of Fish Meals: Contact with Producers and Fewer Fish-Averse Children

In municipalities that actively put local agricultural, forestry and fishery products into school lunch, contact between producers and children develops, and multiple effects such as fewer children who dislike fish have been reported. When fishers or fishery cooperative staff visit schools to talk about how fish are caught and the hardships of the work, or demonstrate filleting, children come to see fish not just as “ingredients” but as “life from the sea.”

Seafood Loss and Our Connection to the Sea

Using fish in school lunch is also connected to seafood food loss. Some caught fish are hard to sell at market because they are small or irregular in shape. Efforts to process such unused or under-used fish for school lunches are under way in various places. The whole picture of seafood loss is set out in detail in Reducing Seafood Food Loss.

Also, in the recovery from the Great East Japan Earthquake, the fishing industry of Sanriku has worked to rebuild aquaculture and processing. That story is told in The Path of Sanriku's Fisheries Recovery. Bringing the bounty of the local sea to children's tables is deeply connected to the recovery of the fishing industry and to sustainable fishing.

Eating up the fish in school lunch is also a way of showing respect for the fisheries that take life from the sea and for efforts to protect its resources. Using a whole fish without waste is a first step toward protecting the sea, whose resources are limited.

Changing Awareness and Behavior Through Food and Environmental Education

Food Education Starts with Learning a Food's “Journey”

In the Ministry of the Environment survey, about 65% of municipalities were running food and environmental education aimed at cutting leftovers. Simply urging children to “finish everything” has limits in reducing school lunch leftovers; it is considered important that children themselves understand why it is better not to leave food.

Initiatives carried out at schools include the following.

1. Making leftovers visible: weigh leftovers by class and by day, and post them as graphs in the classroom
2. Lessons on a food's journey: learn how ingredients travel from fields and the sea to the school kitchen
3. Contact with producers and cooks: come to know the faces and thoughts of the people who make the food
4. Explanations by nutrition teachers: convey the nutrition in the day's menu and its relation to the body
5. Links to environmental learning: think about the relationship between food loss, greenhouse gases and waste treatment

Weighing Leftovers Changes Children's Behavior

In various places, classes weigh and record leftovers every day and children themselves consider how they relate to the day's menu and the time available. Once shown as numbers, children begin to find patterns on their own, such as “There are more leftovers on fish days” or “Soup is left when there was little time.”

What matters is not to turn the numbers into competition between classes. Common to successful schools is using them not to blame classes with many leftovers, but as material for thinking together about “how can we make it easier to eat?” and “what can we try?”

Dialogue with Cooks and Nutrition Teachers Changes the Menu

Two-way efforts are also spreading in which pupils send messages and requests to cooks and nutrition teachers, and menus and seasoning are improved in response. For children it is an experience of their voice being reflected in school lunch, raising their sense of ownership. For the kitchen side, feedback from the field clarifies concrete causes of difficulty in eating and offers clues to improvement.

Teaching the Connection with the Sea

Within food education, dealing with the connection to the sea has special meaning. The fish and seaweed we eat depend on the marine ecosystem and on the work of the fishers who support it. Simply learning the names, origins and catching methods of the fish served at school lunch can lead children to avoid wasting food. In schools near the sea, some combine beach cleanups and fishing experiences with lessons on school lunch.

Getting to know seasonal ingredients is also a useful entry point for thinking about the link between food and nature. For seasonal ingredients and the rhythm of nature, see also What Does Eating in Season Mean?.

Ideas from the Field: Menus, Serving, Time and Systems

Adjusting Portions: A System Where Pupils Can “Adjust” for Themselves

Many schools use methods in which pupils adjust their own portions before serving, instead of giving everyone the same amount. For example, they can choose “large, regular or small” servings of staples and side dishes, or be given time to reduce amounts before eating. Combined with seconds after eating, this satisfies children who need more.

What matters is that teachers repeatedly convey the message that “reducing is not a bad thing.” The ability to estimate for oneself how much one can eat also leads directly to cutting food loss as an adult.

Menus: Improving Items That Tend to Be Left

Recording leftover-rate data by dish reveals which menus tend to be left. Once patterns are clear, measures such as changing seasoning, cutting ingredients smaller or pairing with popular dishes become possible. Some reports say that using local and seasonal ingredients reduced leftovers thanks to better flavor.

Community Systems: Composting and Food Cycles

Some municipalities have set up systems that turn leftovers and cooking scraps into compost used by local farmers and school gardens. Such food cycles not only reduce waste but also become teaching material in which children experience “the food we left becomes nutrients for the next crop.” Composting, however, comes with challenges such as odor, insects and collection and transport costs, and cooperation with local farmers and businesses is indispensable.

Using Data: From “Measuring” Leftovers to “Using” Them

MEXT's March 2023 research report collects examples of reducing food loss in school lunches. Efforts from across the country give hints for choosing what suits one's own school. Recording leftover data daily and checking monthly and termly trends confirms the effect of initiatives and helps maintain motivation.

What Families and Communities Can Do: Making School Lunch Waste Personal

At Home: Don't Blame Dislikes, Increase “Delicious” at the Table

Leftover school lunch is also related to eating habits at home. If children rarely eat fish or vegetables at home, they are not used to them when they appear at school and are more likely to leave them. Yet scolding “Finish your food!” tends to backfire. At home, you can start with the following.

• On a day off, watch together how fish is cleaned and grilled
• Serve seasonal fish and local vegetables and talk about where they come from and the season
• Try disliked foods several times in small amounts and with different cooking methods
• Look at the school lunch menu together and talk about the day's ingredients
• When a child says “I can't finish it,” accept adjusting the amount

The reality of household food loss and concrete ways to reduce it are covered in detail in The Reality of Household Food Loss: 2.36 Million Tonnes a Year.

In the Community: Connecting Producers, Fishery Cooperatives and Schools

Local government, PTAs and community NPOs can also play the role of connecting schools with local producers, fishery cooperatives, agricultural cooperatives and food processors. Creating a contact point that brings local ingredients to school lunch, inviting producers to schools, and holding cooking classes using school lunch ingredients all help protect local food culture.

Food loss is not only a school issue. Convenience stores and retailers are also advancing reduction efforts, such as managing expiry dates and improving demand forecasting. For business-side efforts, see also Food Loss at Convenience Stores.

Summary: Balancing “Reducing” and “Nurturing” in Leftover School Lunch

Leftover school lunch does not account for a large share of Japan's overall food loss. But because it is a place where children face food every day, its educational impact is very large. What efforts to cut leftovers aim for is not “making children finish everything,” but nurturing gratitude for food and the ability to think about an amount that suits oneself.

Bringing local ingredients and fish into school lunch and learning the background of food through contact with producers is not only a way to reduce food loss, but also an opportunity to think about local industry and the marine environment. Why not consider the links among our food, the sea and the future from a single school lunch plate?