Activist groups often cite the quantity of feed or land used by cattle production as evidence we should not consume beef or dairy products, suggesting we could feed far more people if we grew human food crops to provide a vegetarian or vegan diet.
This is logical if we accept the assumption that billions of people would be willing to eliminate meat and dairy products from their diet, which is debatable.
However, recent research showed an entirely vegan diet reduced the number of people that could be fed from one hectare of land, because grazing and perennial cropland that would usually be used for grazing or livestock feed could not be used to generate food.