Diets rich in beef and other red meat can be bad for a person’s health. And the practice is equally bad for Earth’s biodiversity, according to a team of scientists who have fingered human carnivory—and its impact on land use—as the single biggest threat to much of the world’s flora and fauna. Already a major cause of extinction, our meat habit will take a growing toll as people clear more land for livestock and crops to feed these animals, a study in the current issue of Science of the Total Environment predicts.