Miley Cyrus. The Williams sisters. The blind 11th-century Arab poet al-Ma’arri. The only thing uniting this motley crew is that, like 540,000 Britons, they adopted a vegan diet.
Over the past decade the number of people in the UK who have followed Gwyneth Paltrow into the realm of tofu and nut roasts has more than quadrupled. Yet a world without meat or dairy may not be as environmentally friendly as they think, according to a study.
Food policy experts have calculated that widespread veganism could waste more farmland than vegetarianism and even some diets that include meat.
Christian Peters, associate professor of nutrition science at Tufts University in Boston, Massachusetts, said that although livestock used up a huge amount of space, getting rid of the animals would not automatically allow farmers to feed more people.
“You can feed more people [with livestock] simply because you’re producing edible food on land you would not be using otherwise,” he said.
Dr Peters and his team worked out how much farmland it would take to satisfy ten different diets: one based on what Americans eat at present; one with fat and sugar stripped out; five with various mixes of meat and meat-free meals; two vegetarian; and one vegan.
At the moment the typical American needs 2.7 acres of agricultural land to supply the food he or she eats in a year. Most of it is taken up with livestock to satisfy a world-leading appetite for meat and dairy products. This area falls by more than 80 per cent, to 0.3 acres, if you strip out meat.
If you want farmland to feed as many mouths as possible, however, it turns out that the vegan diet is only the fifth best choice, behind dairy-friendly vegetarian diets and mixed diets in which up to half of the meals contain meat.
This is because a good deal of the land that is given over to grazing and growing food for livestock cannot easily be planted with other crops. If the entire population of the US were to go vegan overnight, about 30 per cent of the country’s arable land would go to waste, as well as a large area of pasture.
Although the analysis was conducted on American agriculture, it may have implications for Britain where only a third of land used for farming is judged to be “croppable”. Simply converting fields from grazing or feedstock to other crops is not realistic.
There are drawbacks to the study. Only one of the diets was based on the 2,700 calories the average American really eats in a day: the others were based on the 2,150 calories recommended by the government. Vegans also have other reasons for eschewing meat and dairy than worries about the capacity of farmland. Although the motivations of the 3.2 per cent of Britons who have gone vegan have yet to be studied systematically, the Vegan Society estimates that up to three quarters of its supporters are bothered chiefly by the idea of exploiting animals.
A spokesman said: “This research focuses rather narrowly on land use, disregarding many of the other factors determining sustainability. In terms of greenhouse gas emissions, water consumption, use of other non-renewable resources, and how healthy the food is — all of huge importance for environmental sustainability and food security — veganism comes out on top.”