Could the world even feed everyone on plants? Wouldn't we starve?

The objection

“It’s a nice idea, but you can’t feed eight billion people on plants. We’d starve.”

The answer

The maths runs the other way round. We already grow enough plant calories for everyone, then manufacture a shortage by feeding those calories to animals first.

A farm animal is a calorie incinerator. Feed 100 calories of crops to livestock and you get back roughly 40 as milk, 22 as eggs, 12 as chicken, 10 as pork, and 3 as beef (Cassidy et al. 2013). Cassidy’s team calculated that the crops we currently grow, eaten directly instead of cycled through animals, could feed roughly four billion more people. The system you’re worried about abandoning is already throwing most of the food away.

The land tells the same story. Poore and Nemecek’s Science dataset found livestock takes up the great majority of the world’s farmland while supplying only 18% of calories and 37% of protein. A global shift to plant-based eating would cut food’s land use by about three-quarters, freeing an area on the scale of a continent for rewilding and carbon storage, all while feeding everyone.

What’s left of the objection is the reasonable part: some regions depend on animals locally, nutrition needs care, and no one proposes a chaotic overnight switch. Granted. None of it touches the core fact. The famine risk was never the plants. The waste is the detour through animals.

So the system that destroys most of our food supply by feeding crops to livestock is the one making hunger harder to solve, while eating those crops directly is what would keep more people fed.