Diet for a Small Planet is a 1971 book by Frances Moore Lappé. It was a bestseller in the West, and argues for the potential role of soy as a superior form of protein. It demonstrates the environmental impact of meat production and a contributor to global food scarcity. She argued for environmental vegetarianism—practicing a vegetarian lifestyle out of concerns over animal-based industries and the production of animal-based products.

The book has sold over three million copies and was groundbreaking for arguing that world hunger is not caused by a lack of food but by ineffective food policy. In addition to information on meat production and its impact on hunger, the book features simple rules for a healthy diet and hundreds of meat-free recipes. "Its mix of recipes and analysis typified radicals' faith in the ability to combine personal therapy with political activism."