First it was slow. Then local, then organic. Now it is firmly grass-fed.

As a rare geophysicist studying diet’s environmental consequences, I am asked daily by my colleagues – a bit bemused by my new field yet quantitatively astute and environmentally concerned – about the latest claim made about impacts of food production on the physical environment.

In this role, I get to keep a sensitive finger on the envirofood pulse. Unambiguously, grass-fed beef is all the rage now. Even the New York Times Op-Ed page featured a recent piece extolling the virtues of grazing cattle.