Eating, it turns out, is the most significant interaction most of us have with the environment. Even if we remain cloistered in air-conditioned rooms in front of keyboards and monitors for most of the day, at some point we must eat—and whether it’s a carrot stick or a Big Mac, with our first bite we implicate ourselves in the food system, and the food system is responsible for 30 percent of worldwide carbon emissions. That is to say, almost a third of greenhouse gases are a result of growing, shipping, cooking, and disposing of food.
A good effort in trying to assess the costs of eating out versus eating in. One of the main conclusions is that meats, especially beef, has a very large environmental impact in terms of greenhouse gas emissions.
Eating less meat will lead to better human health, as well as reduce our overall greenhouse gas emissions.
Also see this article at The Guardian.