In the United States, 30 percent of the people have a “weight problem”. To many people the cause is obvious (明显的): they eat too much. But scientific evidence (证据) does little to support this idea. Going back to America of 1910, we find that people were thinner than today, yet they at
e more food. In those days people worked harder physically, walked more, used machines much less, and didn’t watch television.
B．they work too hard |
