[Nathan] Pelletier is one of a growing number of scientists studying the environmental costs of food from field to plate.
By looking at everything from how much grain a cow eats before it is ready for slaughter to the emissions released by manure, they are getting a clearer idea of the true costs of food.
The livestock sector is estimated to account for 18 percent of global greenhouse gas emissions and beef is the biggest culprit.
Even though beef only accounts for 30 percent of meat consumption in the developed world it's responsible for 78 percent of the emissions, Pelletier said Sunday at a meeting of the American Association for the Advancement of Science.
That's because a single kilogram of beef produces 16 kilograms carbon dioxide equivalent emissions: four times higher than pork and more than ten times as much as a kilogram of poultry, Pelletier said.
If people were to simply switch from beef to chicken, emissions would be cut by 70 percent, Pelletier said.