I woke up to the sound of caterpillars munching. No, I can’t hear them, but some plants can. That was proven earlier this year, and now I imagine being rooted, unable to run or hide, hearing the voracious clack, clack, clack of approaching mandibles. What to do? Secrete mustard oil to drive off the fearsome predators. Maybe only lose a few leaves.

And then there’s the sea squirt, that poster child for what’s called retrogressive metamorphosis. What that means is that the larvae of the sea squirt swim around—clearly an animal—but then they attach themselves to a rock and devolve into something a (very) hungry vegan might ethically munch.

People inadvertently experiment with retrogressive metamorphosis when they strictly adhere to raw food diets. Why? Richard Wrangham’s great book, Catching Fire: How Cooking Made Us Human, explains that cooking gave humans the evolutionary edge over other primates. Cooking allows us to utilize a lot more calories in a lot less time than eating raw. Cooking is what fuels our big brains. Eating strictly raw foods means flushing a large percentage of one’s calories down the toilet, which is wasteful, uncomfortable, and reinforces poor decision making.

Dr. Wrangham is a professor of biological anthropology at Harvard—and he’s a vegetarian. That speaks to me as a right choice, arguably the right choice. Raising animals for human consumption is energetically so inefficient that it makes little sense on a planet that is becoming so densely packed with people. Healthy or not, the more we adopt a meat-centric “paleo” diet, the sooner we’ll be eating each other.

Right now industrial farmers use plants to turn fossil fuels into food, but soon technology will remove the middleman. We’ll be able to eat dead dinosaurs directly! Eating will be totally ethical, our mpg will beat a Prius, and we’ll solve global warming. How could conscious folk say no?

In the meantime, is eating meat really wrong? I live on a river where the Takelma Indians and the salmon grew up together: where the salmon were considered one type of “people,” the plants another, and the caterpillars another. I think the Takelma had it essentially right. I also know that salmon—from habitat restoration to fishing licenses to local restaurants—still plays an important role in our community. Of course, restoring rivers for recreational fishing is a ridiculously inefficient way to feed people and “playing” them on barbed hooks is unconscionably cruel. But is it a bad idea? Really?

To borrow from St. Augustine: Lord, make me vegetarian. But not yet!