根据下面资料，回答题
Millions of hamburgers are eaten by people in every comer of the world every day. Together with hot dogs and Coca-Cola, hamburgers have been the most important American contribution( 贡献) to international eating habits.
The name "hamburger" has nothing to do with ham(火腿). It is believed that the hamburger was first brought to the United States by Germans from the city of Hamburg some time in the 1850s. From then on the hamburger became a kind of popular American fast food.
Now young people in Asia, Europe and South America have learned to eat while on the move; a hamburger in one hand and a soft drink in the other. There have been cries to anger from Italy and Spain about the shortening of the usual lunch break. Instead, young people have disc.o-vered a lunch for which they don´ t have to stop at all.
However, there are clouds over the ham_burger´ s world. People who concern bout health dislike the high animal fat in the hamburger. They think the time saved seems a high price to pay for poor health. The packages in which hamburgers are usually served are causing serious pollution problems in many large cities. Big hamburger companies are destroying large areas of South American rainforest to produce the cheap meat they need. So, will the hamburger celebrate its next century?
In which way do hamburgers change people’s eating habits?