Greenhouse emissions per household can be reduced by an amount equivalent to driving a car 1860 km fewer per year if people switch from red meat to veggies just for one day every week, calculates a researcher.
Christopher Weber of Pittsburgh-based Carnegie Mellon University also reckons that a completely local diet may help reduce a household's greenhouse emissions by an amount equivalent to driving a car 1600 km fewer per year.
He said that his calculations, based on an analysis of the environmental toll of food production, suggested that the consumption of locally-produced food items may not be as effective in reducing carbon emissions as quitting red meat for one day in a week.
"If you have a certain type of diet that's indicative of the American average, you're not going to do that much for climate while eating locally," New Scientist magazine quoted Weber as saying.
Weber and his colleague Scott Matthews' analysis included emissions like transporting and producing fertiliser for crops, methane gas emitted by livestock, and food's journey to market.
They observed that the final step added up to just four per cent of a food's greenhouse emissions on average, while red meat spewed out far more greenhouse gases than other foods.
"It seems much easier to shift one day of my beef consumption a week to chicken or vegetables, than going through and eating only Jerusalem artichokes for three months in the winter," said Weber.
Matthew Perry, head of Carbon Label California, said: "If you're interested in the hamburger you're not going to switch to tofu, but you might switch to a chicken burger."
The study has been reported in the journal Environmental Science and Technology.