Chao Zhou

Now days, moore American get farter and farter,one reason is that the U.S economic growth is too fast. The living environment changes alot, people work for a long time, life has given people lots of pressure, they have no time to have a healthy lunch, and then they buy fast food. Every one know that fast food contains a mass of calories, the fast food is not healthy for humans.
Another reason is the transport, more and more people have their presonal cars, they drive car to everywhere. America is a big country, the distance between city and city is far. people have to drive the car to visit. People have no free time to do sports. Science and technology is keeping developing, a variety of machines in place of a lot of manpower, it's seems that it's easy than before, but long-term face of computer is harmful.
America is a real developed country, time always goes fast, a country can become richer and richer, this requires that people continued to work, so people need more energy, that's why American have to get fater and fater.