Study Estimates Ecological Costs of Overeating

The United Nations (UN) estimates that rich countries throw away nearly as much food as the entire net production of sub-Saharan Africa—about 230 million tons per year. But is it any less a waste to eat the excess food?

Morally, it’s equivocal. Nutritionally, it depends. However, the land, water, and carbon footprints are just the same.

In fact, researchers in Italy have proposed a way to measure the ecological impact of global food wastage due to excessive consumption. First, they estimated the net excess body weight of each country’s population—based on BMI and height data—and distributed its energy content among food groups according to national availability.

Published in Frontiers in Nutrition, the results suggest that direct food waste—thrown away or lost from field to fork—is a mere hors d’oeuvre.

“Excess body weight corresponds to roughly 140 billion tons of food waste globally,” reports group lead Mauro Serafini, PhD, of Italy’s University of Teramo.

This figure is a snapshot of the current world population’s accumulated dietary excesses, not a rate of overconsumption. It is, however, orders of magnitude higher than current annual direct food waste, estimated at 1.3 billion tons.

The disproportionate impact of what Serafini’s group deems “metabolic food waste” grows when its ecological costs are calculated, using per-kilo values from thousands of food lifecycle assessments. Fruits, vegetables, roots, and tubers have the highest direct wastage rates, but excess energy consumption is dominated by more calorie-dense foods, which typically entail more land, water, and greenhouse gases to produce.

Indeed, it’s estimated that growing the world’s metabolic food waste would be expected to generate the equivalent of 240 billion tons of carbon dioxide, roughly the amount mankind released burning fossil fuels over the last seven years combined. Notably, the European Union, North America, and Oceania collectively contribute as much to this estimate as the rest of the world combined, with meat, eggs, and dairy accounting for 75%.

The findings suggest numerous variables and areas for further study. For example, the total land and water figures are difficult to interpret, as they don’t take into account how long land is required to grow different foods, or the redistribution of water, which isn’t lost per se via agriculture.

Furthermore, though based on public data collected by the UN, the World Health Organization, and other prominent sources, the approach incorporates a degree of methodological and conceptual uncertainty. The calculations are based on national availability of the main food commodities, not average food intake or typical sources of excess calories among the overweight and obese. The researchers also assumed that bodyweight beyond BMI 21.7, the midpoint of the accepted “healthy range” associated with lowest all-cause mortality, was entirely excessive, ie, all fat. Finally, the way excess body weight may change over time, or how much of it would vanish if physical activity were increased to more healthful levels, are additional variables that would benefit from future study.

— Source: Frontiers