For the average American, walking actually uses quite a lot of fossil fuel, because the fuel the walker uses is the food they eat. Food takes a lot of fossil fuel to produce, and the food that takes the most is meat. It actually takes about 17 times more fossil fuel to get a calorie from meat than it does from wheat or beans. That means if you follow a meat-centered diet, you’re going to indirectly burn a lot of fossil fuel just by walking. Of course, vegetarians use far less fossil fuel.
According to Professor David Pimentel of Cornell University “It is actually quite astounding how much energy is wasted by the standard American-style diet. Even driving many gas-guzzling luxury cars can conserve energy over walking—that is, when the calories you burn walking come from the standard [meat based] American diet!”
It takes a lot of fossil fuel to produce the fertilizers, the pesticides and to harvest all the crops we feed to animals. Also consider that 70% of the crops we grow in this country go to feed farm animals not people. It gets worse. The slaughterhouse, and all the refrigeration and freezing that meat requires, takes even more fossil fuel.
The result of all this is a fantastic inefficiency, and the way out of it is through a meat-free diet. Even better is a meat, dairy and egg-free diet. So, from the point of view of the environment, if you’re not yet a vegetarian maybe it would actually be better for the environment if you drove more and walked less!