A diet with meat is responsible for producing in a year the same amount of greenhouse gases as driving a mid-sized car 4,758 kilometres (2,956 miles), the Institute for Ecological Economy Research (IOeW) said.
But the food a vegetarian consumes in 12 months is responsible for generating the same emissions as driving 2,427 kilometres, the IOeW said in a study commissioned by independent consumer protection group Foodwatch.
The calculations are based on emissions of greenhouse gases, including methane produced by the animals themselves, as well as emissions from food production including manufacturing feed and fertiliser and the use of farmland.
Going vegan -- giving up meat and dairy products -- would cut the emissions released in making what you eat more than seven-fold, to the equivalent of driving 629 kilometres, it said.
And if it is all organic, your food footprint is almost a 17th of that of a meat-eater -- the equivalent of driving 281 kilometres.
Beef is particularly environmentally unfriendly, it said, with producing a kilo (2.2 pounds) the same as driving 71 kilometres compared with 26 kilometres for pork.
Switching to organic farming can cut emissions dramatically, "but what counts is the way we feed ourselves ... production and consumption first and foremost of beef and milk must be cut drastically," the study said.