High-quality diets high in fresh vegetables and fruits are linked to as much, if not more, greenhouse gas emissions as low-quality diets that are high in sweets and salts, say French scientists. Picture: THINKSTOCK
High-quality diets high in fresh vegetables and fruits are linked to as much, if not more, greenhouse gas emissions as low-quality diets that are high in sweets and salts, say French scientists. Picture: THINKSTOCK

Washington — What would a vegan America look like? A herbivore population would enjoy a drop in greenhouse-gas emissions, but also face deficiencies in calcium, vitamins A and B12, and fatty acids.

That’s according to a new study by the US department of agriculture and Virginia Tech University, which studied the possible impact of eliminating animals from the nation’s food production and putting citizens on a plant-based diet.

The total American food supply would increase by 23%, as corn, soybeans and other crops fed to animals would be diverted to other uses, according to the study, published in the Proceedings of the National Academy of Science this month. Still, because land used to grow feed crops is often unsuited for fruits and vegetables, such farms would likely stay with grains, adding to a glut in commodities, the researchers said.

"We need to expand the way we think about food production to account for the complex consequences of changing any individual piece within the wider food system," Robin R White, a professor at Virginia Tech who co-wrote the study, said in a statement on Tuesday.

Vegan diets, whose proponents include former president Bill Clinton and talk-show host Ellen DeGeneres, eschew all animal products, differentiating themselves from vegetarians, who are primarily concerned with meat.

A complete shift from food-animal production would end meat, milk, egg, fish and cheese consumption, presenting nutritional challenges for many Americans, according to the study. A plant-only diet would also require individuals to consume more calories overall, as many foods used to replace animal-based products are less-dense in nutrients, the researchers said.

A move toward nationwide veganism would be planet-friendly, though, with its greenhouse-gas reduction. The loss of the livestock industry would more than offset the increased fertiliser and fossil-fuel use necessary in an exclusively plant-based system, the study said. Total US emissions would fall by 2.6% as those for agriculture slump 28%.

The study didn’t offer any analysis of the personal impact of veganism, saying that individuals can take many paths toward a healthy, balanced diet.

Said Mary Beth Hall, a US department of agriculture researcher in Wisconsin, and a co-author of the study, in the statement: "There’s a difference between what’s possible when feeding one person versus feeding everyone in the US,"

Bloomberg

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