A new study suggests that food waste cost estimates may be too high.
The Food and Agriculture Organization of the United Nations reports that one-quarter to one-third of all the food produced worldwide is wasted, and some estimates point to waste numbers at 40% or more.
“The extent of food waste — in terms of quantity and value — appears overstated in many cases,” Marc Bellemare of the University of Minnesota, said in a news release.
Bellemare and other researchers recently released “On the Measurement of Food Waste,” a paper published in the American Journal of Agricultural Economics.
The research essentially defines food waste as whatever is produced in the food system that ends up at the landfill.
The authors say one problem with current food waste cost estimates is that they value all food waste — regardless of where it occurred in the supply chain — simply at the retail transaction price. 
“Values are overestimated due to both overestimation of the quantity and price of food waste,” according to the the University of Minnesota paper.
The authors calculate the cost of food waste at 27.6% of total food produced, compared with the U.S. Department of Agriculture’s cost estimate of 57.6% (according to the USDA-Economic Research Service) and the Food and Agricultural Organization’s estimate of 39.6%.
Bellemare said in the release that, from an economic perspective, food waste is a byproduct of improved living standards.
“Worldwide, there is a positive relationship between income per capita and the amount of food wasted per person,” he said in the release.
In developing countries, where food waste contributes to food insecurity, the paper said food waste largely occurs at the production, processing, and distribution stages before food is purchased by consumers. 
In contrast, in developed countries, the bulk of food waste occurs after food is distributed to food businesses and retailers and is sold to consumers.
Different policies are needed in developing and developed countries to address food waste, according to the authors.
The paper outlines what the authors call a “more consistent and practical approach” to measuring food waste and identifies the specific and strategic areas policy makers could employ in dealing with the problem.
The authors argue that the food waste definitions should ignore edibility and account for whole plants and animals produced for food.
“Thus, stalks and leaves and hide and bones should be fully accounted for in our calculation, noting the stages where they are discarded from the food supply chain, potentially redirected for food use or non-food use, or added to the landfill,” the paper said. 
While that way of estimating food waste would result in a larger estimate of the volume of food-related organic waste, it would also be the most useful when used in connection with policy goals set using the same definition, the paper said.