Want to save the planet? Check what's at the end of your fork.

From production to consumption to waste, the world's food system accounts for a hefty slice — about 33 per cent — of what's heating up the planet, says Anna Lappé in her book, Diet for a Hot Planet, to be published April 10. She argues that we need to radically change how food is produced and what we eat.

Lappé is co-founder of the Small Planet Institute, a nonprofit research network, and was named one of Time magazine’s “Eco Who's Who.”

Lappé, 36, who lives in Brooklyn, N.Y., talked to the Toronto Star about some of her findings.

Q. You say one-third of the planet's warming comes from the global food chain. So many numbers are bandied about. What's this based on?

That number is from data from groups such as the United Nations Food and Agriculture Organization and the Pew Center on Climate Change, among others. It comes as a surprise to a lot of people. Only last year did the media, at least in the U.S., talk about the connection between food and climate change.

Q. Why is that?

Talking about food and climate change requires thinking of food as a system. A lot of us go to the grocery store and don't think about the story behind the food on the shelf. Also, focus has been on the main sectors contributing carbon dioxide, the most significant greenhouse gas.

Q. The biggest single offender is livestock production, accounting for 18 per cent of global warming. Why is that?

It’s not the cow's fault. It’s the deliberate choices made by the food industry and livestock producers to turn to highly wasteful and highly energy-intensive factory farm systems.