Why and How to Measure Food Loss and Waste

Selecting Key Performance Indicators and Identifying Impacts - Why and How to Measure Food Loss and Waste

Measuring FLW should go beyond simply measuring the amount of food that leaves the food supply chain. This measurement fails to capture the impacts and benefits of reducing and preventing FLW. Preventing FLW has far-reaching economic, environmental and social benefits that can also be tracked.

Which Impacts Should I Track?

Key performance indicators can determine an organization’s success in achieving an objective or evaluating activities. Using a well-chosen suite of metrics, organizations can find out if they are achieving FLW prevention, redistribution or diversion. These metrics can also evaluate progress and tailor future interventions. Possible impacts fall into three broad categories:

  • environmental impacts;
  • financial impacts; and
  • social impacts.

Organizations can monitor progress (and communicate success) more effectively if they use a range of appropriate metrics and consider reporting results in all three categories.

Environmental Impacts

Food production and all its associated processes (including processing, manufacturing, packaging, distribution, refrigeration and cooking) require resources, such as arable and pasture land, fresh water, fuel and chemical inputs (e.g., fertilizer, herbicides and pesticides), and cause environmental impacts, such as air and water pollution, soil erosion, emissions of greenhouse gases and biodiversity loss.

Depending on its management, FLW can cause additional environmental impacts that would not have occurred had the food been consumed. Some of these are associated with transportation of waste, land uses for landfills and methane emissions from landfills. While less important than impacts associated with production, these impacts can still be significant.

Examples of environmental impacts that an entity could track alongside FLW data are: greenhouse gas emissions, use of water, land, fertilizers and energy and biodiversity loss.

Greenhouse Gas Emissions

Greenhouse gas (GHG) emissions are the most commonly tracked environmental impact related to FLW. For most food products, the GHGs can be determined by a lifecycle analysis (LCA), which provides a full picture of the GHGs associated with the production of a food item from the point of production to the point at which it is lost or wasted. Each food item has a unique set of GHG factors depending on the land and resources needed to produce it. The GHG impact factors increase the further along the supply chain FLW is generated.

Much LCA data is publicly available. The sources below provide GHG impact factors.

The US EPA Waste Reduction Model (WARM) can help to assess the GHGs associated with FLW. WARM provides estimates of GHG emissions associated with baseline and alternative waste management practices, including source reduction, recycling, anaerobic digestion, combustion, composting and landfilling.

Water Use

Water is used throughout the food supply chain, including to water crops, in manufacturing processes and to wash food waste down the drain to a sewer. Three types of water can be considered when assessing environmental impacts (Hoekstra et al. 2011):

  • Blue water – water withdrawn from ground or surface water sources (e.g., irrigation water)
  • Grey water – the water required to dilute polluted water for it to be safely returned into the environment
  • Green water – water evaporated from soil moisture (e.g., rainfall)

Most estimates of environmental impacts include only blue water and grey water, although green water is relevant in water-scarce regions.

The largest database of water impacts is from the Water Footprint Network, with the Water Footprint Assessment Tool being especially useful (Water Footprint Network 2018). When using the tool, select “Production Asssessment” and select the commodity of interest as well as its country of origin to access the data of interest. The Water Footprint Network also provides country-specific blue, grey and green impact factors for crop and animal products.

Although GHGs and water are the most common environmental impacts measured in association with FLW, several others are relevant. Because these impacts are less frequently quantified, they have fewer measurement resources.

Land Use

The impact on land use is more complicated to measure than the impact on GHGs or water. Some complicating factors are multiple cropping (where multiple crops are harvested from the same land within the course of a year) and crops that have multiple-year cycles, such as sugarcane. No simple, easily available tools yet exist to calculate land use associated with FLW but the Food and Agriculture Organization of the United Nations (FAO) Food Wastage Footprint provides global estimates of land used for food that is lost or wasted, as well as the relative impacts of a range of commodity types (FAO 2015).

Fertilizer Use

At the production level, fertilizer use associated with food loss or waste can be roughly estimated by multiplying the percentage of FLW by the total amount of fertilizer used. However, no simple method exists for other stages of the supply chain where the total fertilizer input may not be known. One study has estimated fertilizer loss at the country level using data from the FAO database, FAOSTAT (Kummu et al. 2012, FAO n.d.).

Energy Use

Most environmental impact estimates do not break out energy use from GHG estimates, but one US study found that energy embedded in wasted food represented about 2 percent of the country’s annual energy use (Cuellar and Webber 2010). The Provision Coalition’s Food Loss and Waste Toolkit based on Enviro-Stewards’ approach may help companies assess energy use relating to FLW.

Biodiversity Loss

Biodiversity loss associated with FLW is an emerging topic. Food production is the leading driver of biodiversity loss through conversion of natural habitats to farmland, intensification of farming, pollution and, in the case of fish, over-exploitation (Rockstrom et al. 2009). Some of this biodiversity loss occurs to produce food that is wasted. At the time of publication, no simple resources existed to assist in assessing potential biodiversity loss. However, tools may by developed in the future.

Financial Impacts

Most of the financial impacts of FLW are associated with disposal, however the total cost of FLW includes all resource inputs wasted along with the food. Simply focusing on disposal costs overlooks the vast majority of financial opportunities and benefits of preventing FLW. Quantifying the costs of FLW might typically involve assessing the following items:

  • The purchasing costs of the incoming food and/or ingredients;
  • The costs added to the food within the business (e.g., relating to labor and utilities,); and
  • The costs associated with redistribution of surplus food or the disposal and treatment of FLW.

Financial impacts that can be tracked alongside FLW data include the following examples:

  • The value of the food that was lost or wasted;
  • The cost of FLW as a percentage of food sales; and
  • The cost and benefits of investment in a food-waste-reduction program.

Two direct measurement tools can capture the weight of FLW and translate it into dollar values: smart scales in the food service sector (e.g., LeanPath or Winnow tools) and the Provision Coalition’s Food Loss and Waste Toolkit for manufacturers.

Social Impacts

Social impacts refer to the effects of FLW on humans. Examples of trackable social impacts are the value of the donated food, the nutritional content and meals wasted.

Donation Amount

A company may wish to track the amount of food it donates to food banks and other nonprofits. Records of these donations are usually kept and just need to be collated. If a company does not maintain records, food banks may record how much food they have received from each company.

Nutritional Content of FLW

The nutritional content of FLW can be assessed in several ways, including calories, macronutrients (i.e., carbohydrates, fat and protein), fiber and other micronutrients. The most comprehensive database of food types and their associated nutrients is USDA’s National Nutrient Database for Standard Reference, which contains information on 8,100 food items and 146 components, including vitamins, minerals, amino acids and more (USDA n.d.). By sorting FLW by food type and multiplying the amount of FLW by the nutrient of interest in the database, you can estimate the nutritional content of the FLW.

Meals Wasted

Expressing FLW in terms of meals wasted can show laypeople the impacts of FLW. Meals are generally expressed as a number of calories, usually 600–700.[1] To determine the number of meals wasted, first determine the total caloric content of the waste using the USDA National Nutrient Database for Standard Reference, then divide that number by the calories in a typical meal. This will provide a total number of meals, although it should be specified that these are not necessarily healthy or complete meals. Calories are just one measure of nutrition and depending on the type of FLW, meals may not be the best measure.

[1] There is no correct number of calories to consume per day (since proper intake depends on energy expenditure) but several health organizations suggest 2,000 calories per day for an adult as a reasonable average. Therefore, assuming three meals a day, the average meal would be 600–700 calories.