【单选题】

In the United States, 30 percent of the adult population has a "weight problem". To many people, the cause is obvious: they eat too much.But scientific evidence does little to support this ide

A、Going back to theAmerica of the 1910s, we find that people were thinner than today, yet they ate more fooD、In those days people worked harder physically, walked more, used machines much less and didn’t watch television.Several modern studies, moreover, have shown that fatter people do not eat more on the average than thinner people. In fact, some investigations, such as the 1979 study of 3,545 London office workers, report that, on balance, fat people eat less than slimmer people.Studies show that slim people are more active than fat people.
A、study by a research group at Stanford University School of Medicine found the following interesting facts:The more the men ran, the more body fat they lost.The more they ran, the greater amount of food they ate.Thus, those who ran the most ate the most, yet lost the greatest amount of body fat. In comparison with the adultAmerican population today, theAmericans of the 1910s_________.
A、ate more food and had more physical activities
B．ate less food but had more activities
C．ate less food and had less physical exercise
D．had more weight problems