Humans are Going the Wrong Direction in Terms of Meat Consumption

As a species, humans are omnivores, being able to subsist on a range of foods, although we are closer to herbivores than we are to carnivores. A new study published in the Proceedings of the National Academy of Science and reported by Nature.com suggests that, unfortunately, humans are moving more toward meat in their diets, rather than less. This is bad for health, and bad for the environment. Not surprisingly, perhaps, the biggest culprits are the world's two most populous nations.

The fast-growing economies of China and India are driving a global increase in meat consumption, cancelling out decreases elsewhere, according to a comprehensive study of global food consumption.

The work, published today in Proceedings of the National Academy of Sciences, takes a detailed look at what people eat, as well as trends from one country to the next. It is also the first time that researchers have calculated humanity's trophic level, a metric used in ecology to position species in the food chain.

Calculating human trophic levels reveals our place in the ecosystem and can help scientists to understand human impact on energy consumption and resource strength. Calorie for calorie, the environmental impact of producing meat — in terms of everything from carbon emissions to water use — is typically many times larger than that of producing vegetable foods. Furthermore, a 2006 FAO study2 found that the livestock industry is directly or indirectly responsible for 18% of global greenhouse-gas emissions — a larger share than all modes of transport combined. “If we all increase our trophic level, we’ll start to have a bigger impact on ecosystems,” says Bonhommeau [the French scientist directing the study].

This kind of study needs to be a wake-up call for all of us to rethink how we eat--both in terms of improving our health (more vegetables are better than more meat), and in terms of moving toward global sustainability of the food supply.