Around the world, wealthier consumers are wasting far more food than less affluent people, tossing out twice as much food as commonly believed, new research suggests.

A newly created international database of global and country-specific food waste found that when consumers reach a spending threshold of $6.70 per capita per day, food waste rises rapidly at first, but begins to slow down as people become more affluent. The food model found that calories are more than double previous estimates of 214 Kcal wasted per day in 2015 (kilocalorie is another word for a calorie). Rather, people are throwing out as much as 527 Kcal every day.

It’s the first attempt to link food waste to consumer attributes like wealth and other socio-economic considerations such as income, education, residence, and food-culture. Previous estimates focused solely on the production and supply of food, which “grossly underestimate” the extent of food waste.

“The analysis introduces a new concept – the affluence elasticity of food waste and shows that it increases rapidly at first but then tapers off as affluence increases,” write the authors in PLOS One. “The new elasticity concept and associated findings have implications for the theory of income elasticity of consumption, and insights for policy practitioners.”

Food waste is elastic, according to new findings from Wageningen University and Research, The Netherlands. As a person gains wealth, they tend to waste an increasing amount of food but that amount of waste gradually levels off as their wealth stabilizes. The long-held estimate of food waste by the Food and Agriculture Organization of the United Nations (FAO) found that about one-third of all food available for human consumption was wasted. That number has held since 2005, but researchers say that the previous findings represent “only one part of the story.” That’s because the method does not factor in consumer behavior and food waste, but only food supply.

“To account for the demand side, one needs to look at uses of food available for human consumption (waste being one), and factors that determine how much food is wasted by consumers,” write the study authors.

To come to their conclusions, researchers looked at food waste as a result of decisions after food is made available to consumers – it’s either eaten or it's not. They then used the human metabolic model, which calculates energy from food consumed spent on maintaining current body weight, to determine the energy requirements of people needing to maintain their body weight or activity level. This was then compared against annual per capita income.

“The choice of attributes can be wide but as a first step, we start with the most basic of all – consumer affluence. Consumer affluence is an often-cited but never quantified determinant of food waste; with claims that the richer populace waste more than their poorer counterparts,” write the authors, adding that data from FAO may not be complete. For example, low-income country surveys don’t necessarily include food from subsistence farming. By comparison, Americans waste about 1 pound of food every day. 

The findings could help efforts to reach the United Nations Sustainable Development Goal 12 to “ensure sustainable consumption and production patterns” by minimizing the use of natural resources and toxic materials, emissions of waste, and pollutants, which can be linked to the production and transportation of food. To achieve lower food waste, the study authors say that the world needs to both reduce food waste in high-income countries and prevent waste from rising rapidly in lower-middle-income countries where affluence is rising the quickest.