With every unfinished meal since Band Aid, you’ve heard it: “people are starving in Africa, y’know.” True, the UN estimates that rich countries throw away nearly as much food as the entire net production of sub-Saharan Africa — about 230 million tonnes 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 bodyweight of each country’s population — based on BMI and height data — and distributed its energy content among foods 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’Ĺ“uvre.

“Excess bodyweight corresponds to roughly 140 billion tonnes of food waste globally,” reports group lead Prof. Mauro Serafini, of the University of Teramo. This figure is a snapshot of the current world population’s accumulated dietary excesses, not a rate of overconsumption. It is, though, orders of magnitude higher than current annual direct food waste, estimated at 1.3 billion tonnes.

The disproportionate impact of Serafini’s so-called ‘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. These typically entail more land, water and greenhouse gases to produce.

More at Frontiers