September 2007

Truth in Trash: Investigating Waste Reveals Food Behaviors
By Libby Mills, MS, RD, LDN
Today’s Dietitian
Vol. 9 No. 9 P. 84

Trash may be smelly, but it’s not useless. Food waste is helping some dietitians who don’t mind getting their hands a little dirty gain insight into eating habits and lessening the burden of garbage.

To understand eating and food behavior, dietitians are picking up shovels along with their usual trade tools to dig beneath the practiced frontiers of dietetics, using the title foodie-ologists. Foodie-ologists crossbreed their dietetics roots with elements of archaeology, anthropology, and sociology. The results lead dietitians from the beginning of mankind to the present and even into the future as they take a closer look at the by-products of living.

Hmm … this may sound like a lot of garbage, but one man’s trash can be another’s treasure. What people leave behind provides insight into society, daily life, nutrition, food practices, and culinary development. It recreates history, supports dietetics application, and foretells the future.

Ancient Digs in Archaeology
Wanting to know the origins of food and dietary behavior and how each era progressively evolved into the next is a natural curiosity. But the past is long and filled with oversimplified images of man spear-hunting mammoths, roasting them over a fire, and surviving for months on the smoldering meat.

Before man turned from hunting and gathering to agriculture, the daily menu was whole foods. Indeed, mammoths and other animals were campfire favorites, as were foraged nuts and berries. Discovering ancient bones and carbonized seeds and shells supports this prehistoric menu. But Deborah M. Pearsall, PhD, archaeologist and paleoethnobotanist at the University of Missouri, clarifies: “With such little evidence, we are left to make inferences about the nutrition and health of these humans.”

Until recently, food knowledge was based on indirect food evidence: site location, grinding stones, sticks, cooking vessels, and other artifacts. Archaeologists compared the relationships of the site findings to figure out how they may fit into ecological, social, and food systems.

Direct evidence of food is limited by its very nature. Organic food deteriorates over time. When food was around and prepared, people ate it—leftovers and stored food are modern practices—and scraps and waste often became dinner for rodents and other scavengers. “Cooking accidents, resulting in charring of foods, can result in preservation of food remains for long periods. These remains can be difficult to identify, however, since they are blackened and often broken,” says Pearsall.

So, how exactly did we evolve from spit-roasted mammoth for dinner to crawfish étouffée?

Today, coexisting food evidence can be retrieved from artifacts using flotation and other extraction methods, isolating isotope signatures, identifying plant-specific starches, and conducting carbon-14 analyses. Even with this evidence, Pearsall says, “Archaeologists can really only say what food was found, a little about how it was prepared, and some about what other foods might have been prepared with it.”

Recently, starch microfossils of Central and South American chili peppers allowed researchers to date pepper cultivation back 6,000 years. The research also links maize with the chilies.1 The new world Native Americans used an all-purpose pounder to crush the maize, manioc (tapioca), and chili pepper, describes Pearsall. Even with no visible evidence of debris, the starch could be isolated.

One possible inference is that chilies were used in combination with the starchy maize and manioc. Nutritionally, the dish provided needed calories and notable amounts of vitamins A, C, and E. This flavorful culinary combination could have had social, medical, ecological, economic, or other symbolic value, but beliefs and practices can only be theorized within the context. With so many gaps in the evidence, cross-discipline discussion is vital.

Now, pepper mush is not the same as crawfish étouffée. But single foods were used as product ingredients as evidenced by loaves of bread found under Mount Vesuvius ash in Pompeii, Italy, and in Egypt during the Pharos. Though people consumed multiple ingredients, as confirmed by South American mummies’ feces, creating the scientific thread connecting what was really eaten and how the food was prepared is difficult.

Varying by region, culture, and time, eating and food behavior are part of a basic food and social system. One food system model frames food into stages: procurement, processing, distribution, consumption, and disposal. In this context, inferences for charred tuber artifacts may be that they are cooked leftovers or waste that was not fully burned.

Social system models allow inference about daily life. Matching cut marks on animal bones to the animal’s physiology stimulates thoughts of ancient butchering methods, cuts of meat and cooking methods, and distribution or storage. At the site, archaeologists would look for a specific butchering structure, tools used, and distribution site such as a market. Meat may have been divided up by family or social position, used as exchange similar to money, to serve political homage or as tax, or destroyed as a potlatch.2

Food both influences and is influenced by these systems. Exploring the past fosters understanding of our culinary, social, and environmental evolution to the present.

From Kitchen to Curbside
Fresh garbage—and lots of it—is a foodie-ologist’s dream. Never before has a society produced so much trash. Found at the throwaway point, curbside, and in landfills, the volume has changed the level of interpretation and broadened the scope of foodie-ology to include garbology, or the study of trash.

Dietitians largely focus on food production, processing, purchasing, and enjoyment as it relates to health. But what people throw away can be equally informative in dietary assessment, behavior intervention, and monitoring.

“Out of sight, out of mind” describes the human-food consumed/trash relationship. From 1987 to 1995, The Garbage Project, a University of Arizona nationwide study, found self-reports of eaten food didn’t match the garbage generated. Like nutrition assessments, discrepancies occurred with recall accuracy, selective reporting, and withholding information. Perceived “good” behaviors were overreported while “bad” behaviors were underreported. Household matriarchs overreport all food-related behaviors by 10% to 30%.

Garbage data can tell us about food behaviors of groups, time periods, and households, as well as nutrition adequacy and cost-effectiveness. For example, the School Nutrition Dietary Assessment Study-I found that students throw away up to 12% of their provided food. Girls and younger children wasted more but not exceeding 15% of total calories provided. Losses are estimated to cost $600 million.3 While many students chose nutritious meals, vegetables and salads were trashed most often along with their vitamin B12 (folate) and fiber, according to the U.S. General Accounting Office.4

A fad to some and survival to others, dumpster diving has spawned new social groups congregating through blogs, meetups, and communities. Spotted at night raiding grocery store and restaurant dumpsters, the “Freegans” are motivated by simple living, camaraderie, and anticommercialism. Outside 35th Street Market in New York, divers can find fresh apples, lemons, bags of prepared vegetables, eggs, and other processed foods. Though the food may be edible, food safety is of concern. But locked dumpsters waste what is edible and risk the survival of the needy.

While Americans discard an average of 4.1 pounds of food waste each week, thousands are throwing away 15% of their purchased solid food. Digging through curbside trash may provide the answer to some foodie-ologists’ suspicions: “Do people really live off of fast food?”

The Garbage Project sorted curbside trash into specific categories, such as type of packaging, brand, and solid or fluid content remaining. Food waste was further categorized as “previously edible” and “preparation by-products.”

This sorting brought to light several interesting points, such as consumers who repeatedly used the same ingredients and foods had greater success with applying health recommendations, culinary knowledge (storage and preparation), and wasting less.

In 1973, when beef was less available, consumers purchased low-cost, unfamiliar cuts and large quantities of beef. Lack of storage and preparation knowledge was evident with more edible beef ending up in the trash. The project also showed evidence that fresh red meat purchases decreased, and consumers were cutting away more fat in response to a scientific link between red meat and cancer. However, people replaced fresh meats with ones such as salami, hot dogs, and bologna.

People wasted 10% of regularly eaten white bread compared with 35% of less frequently eaten rolls, hot dog buns, and muffins. Hispanics wasted less food than Caucasians, possibly because Latino cooking, though varied, relies on limited ingredients, while Caucasians typically cooked with more ingredients.5

Applying these insights to how we influence consumer behavior gives direction to food product development, recipe development, meal planning, introduction of new recipes, food preparation, cooking, and storage.

Landfill Legacy
Waste management can reveal who we are, how we live, and what we value. In a sense, the truth of a society is in the trash, and garbage is the legacy we leave behind. The better we manage waste, the less there will be for future generations.

Garbage is big business. Managing municipal solid waste (MSW) is necessary, expensive, and revenue generating. Owning a landfill is for life—filling it and the 30-year commitment postclosing to ensure the safety of the site. Environmental protection protocol protects against leakages from hazardous waste such as leftover pesticides, motor oil, paint, toxic liquids, and methane gas production.

MSW accounts for household trash. In the mix of appliances, furniture, and clothing, a significant portion comes from food packaging and food remnants. Food waste alone is the third largest component by weight. Most food waste is from fresh fruits and vegetables, dairy, and grain products, according to the USDA.

Like other stages of our food system, garbage has market value at various levels. From the service of convenient curbside pickup to recyclable sales or imports of volume-dependent trash, garbage management generates a great deal of money. With trash traveling coast to coast, its environmental and pocket price increase with the use and cost of fossil fuel. Food waste represents food for animals and nutrients necessary for replenishing the soil and growing the most nutritious produce.

Redirecting 11.9% of the 245 million tons of U.S. household garbage generated per year can have a significant impact.6 Additionally, finding workable channels for food waste requires a local strategy. Keeping trash within the community creates new business, provides jobs, feeds animals, and enriches the land. Revenues and benefits stay local.

Reducing and rechanneling garbage requires financial and legal incentives and education. The goal should be to reduce the impact of trash now and in the future by considering a host of ecological, social, and economical factors. This may include source reduction, recycling, composting, and a movement for zero food waste.

Corporations have successfully made strides in trash reduction by using lighter and less packaging materials. The military meal, ready to eat is a perfect low environmental impact example with lightweight, low-waste packaging easily carried with minimal field waste. Consumers, however, have had varying degrees of success, the most accepted being the use of garbage disposals. This diversion of food waste from the landfills is food for the environment, but it reduces the amount of valuable data for the serious foodie-ologist.

Recycling is well accepted at the commercial and consumer level. Oil from restaurant kitchens is regularly picked up for recycling into biofuel. Separate bins for paper, glass, and plastic food packaging can be found in public areas. According to the 2006 Wisconsin Department of Natural Resources survey, more than 90% of households supported the recycling program.7

Orange County, N.C.: Composting Made Easy
“Dollar for dollar, this is one of our most effective recycling programs,” says Robert Taylor, recycling program manager for Orange County, N.C., referring to a program that turns 1,850 tons of food waste from 120,000 residents and more than 25 commercial kitchens into compost each year.

“We try to lead by example by collecting food and organic waste at county functions, and when reusable utensils are not an option, using biodegradable cornstarch-based flatware and paper plates, and then composting reduces waste,” he says.

Taylor’s program is one of a growing number across the nation with the goal of zero food waste going to landfills. Yet, of the 4,000 U.S. composting facilities, no more than 150 accept food waste.

Each program varies by region and community. While Taylor’s program started with local pig farmers collecting food scraps from restaurants for feed and has moved on to the broader collection of compostable organics such as waxed cardboard and food-contaminated paper from restaurants, cafeterias, and grocery stores, others, such as in Dubuque, Iowa, have graduated to an incentive-based, curbside pickup that redirects 20% of household waste.

Supermarkets, hospitals, and industrial kitchens generate large volumes of organic waste. Massachusetts started the Supermarket Recycling Program Certification for more efficient transportation, bypassing inspection stations for hazardous or state-banned materials. In 2006, the program had 80 smaller supermarket participants. From Massachusetts to Washington, the ban of food waste from landfills is on.

In addition to incentives, public education will be key. Waste management, specifically using food waste as feed and compost, creates a cycle out of the otherwise linear concept of food from farm to plate.

As advocates of the public’s nutrition health and a wholesome food supply, we can’t wash our hands of waste management; it’s part of our mission. Better practices of food waste management can save money, inspire culinary skills, reduce waste, and promote environmental stewardship.

In the future, there may be no organic food remains to study. Dietitians gone foodie-ologists will have, instead, the health of our livestock and quality of our growing soil.

— Libby Mills, MS, RD, LDN, is a speaker, an author, and a wellness consultant.

Fact: In 1995, plastic shopping bags were in only 1% of landfill garbage, taking 1/5 the space of their nondegrading paper counterparts.


1. Berger JM. “Chili peppers on the menu for at least 6,000 years.” The Boston Globe. February 19, 2007. Available here. Accessed July 29, 2007.

2. Samuel D. “Approaches to the Archaeology of Food.” Petit Propos Culinaires. November 1996. Available here.

3. Guthrie JF, Buzby JC. “Several strategies may lower plate waste in School Feeding Programs.” Food Review. Summer-Fall 2002. Available here. Accessed July 29, 2007.

4. Lee HS, Lee KE, Shanklin CW. Elementary Students’ Food Consumption at Lunch Does Not Meet Recommended Dietary Allowance for Energy, Iron, and Vitamin A. J Am Diet Assoc. 2001;101(9):1060-1063.

5. Rathje WL. “The Garbage Project & ‘The Archaeology of Us.’” September 8, 2005. Available here. Accessed July 29, 2007.

6. Environmental Protection Agency. Available here. Accessed July 29, 2007.

7. Wisconsin Department of Natural Resources. DNR 2006 Recycling Survey Executive Summary. Available here. Accessed July 29, 2007.