The study showed that even though meat and dairy take up 83 per cent of global agricultural land, they only provide 18 per cent of global calories and 37 per cent of global protein consumption. In other words, animal products are staggeringly inefficient - there is a massive disparity in the amount of resources we put into animal farming compared to what we get back. Simply put, the consumption of animal products is just not tenable in a sustainable food system.
— This Is Vegan Propaganda by Ed Winters (Page 102)