 Our health, our children's health, and the health of the planet are intimately connected, and in general the choices that are healthiest for us turn out to be healthiest for our planet as well. Many of us know that vegetables are important for our health and that we should try to kind of limit the amount of meats in our diets or the frequency with which we eat meat. But it turns out that if we replace some of the meat in our diets with vegetables that actually turns out to be better for the earth as well. Modern methods of producing meat actually hurt our environment. Let's take a look at beef for example. So historically cows got energy from grass and the grass got energy from the sun. Now the cows in turn give nutrients back to the grass that they're eating through their manure. I don't know if they've ever heard the saying don't poop where you eat, probably not, but the point is that that manure actually fertilizes the grass to grow even more. And this is what we call a closed loop system because the inputs, in this case sunlight which is free and the outputs of this closed loop are in this case manure and this manure becomes a nutrient input again and this is why we call it a closed loop system. These days we produce meat very differently. Instead of grazing on grass in a pasture, most cows are typically found eating corn in factories that we call concentrated animal feeding operations and the abbreviation for that is CAFO and a CAFO is kind of like a city or a slum for cows. The reason that we raise cattle in CAFOs and feed them on corn comes down to simple economics. Corn is cheaper than grass because the government incentivizes or pays farmers to grow lots of corn. Because CAFOs are really tightly packed like slums, they can yield thousands more cows per acre than a pasture can and when cows eat corn instead of grass they fatten up more quickly which means that they can go to market more quickly as well. But these cheaper prices don't take into account the enormous cost to the environment and to our health. Meat is free and it's free of greenhouse gases but when we move to CAFOs where cows are eating corn there are a lot of inputs besides sunlight. When farmers grow corn they use fossil fuels and fossil fuels are used to make pesticides and fertilizers and to power the tractors of the machinery that harvest and transport the corn. Now these fossil fuels are big contributors to global warming. Also huge amounts of manure collect around the CAFOs in enormous lagoons of waste which harm the air and the water for miles around. Unlike in the system where cow manure fertilizes the grass that it eats, this manure has nowhere to go and it's produced in such enormous quantities that it's difficult to move anywhere else. When cows live in such crowded conditions they're also much more likely to get diseases so farmers feed them antibiotics to make sure that they stay healthy. Eighty percent of the antibiotics used in the United States go to this kind of commercial production of animals and it's really dangerous for our health because it leads to antibiotic resistant bacteria. These are superbugs that can cause diseases that we can't treat with regular antibiotics. So let's look at a chart that will kind of help us see the difference in greenhouse gas emissions of meat versus other things like fruits, vegetables, tofu, and beans. So for a kilogram of beef twenty seven kilograms of greenhouse gases are added to the environment. Now for a kilogram of let's say broccoli or a kilogram of tofu only about two kilograms of greenhouse gases are released into the environment. Also different meats are relatively better for the environment. For example chicken is more energy efficient than beef and also because it has less saturated fat than beef it's probably better for your health as well. So the message is limit red meat consumption, pick lean or energy efficient proteins like chicken or vegetable sources of protein more often and in general choose vegetables more often.