According to the results of a Pew Research Center phone survey of 2,250 randomly chosen American adults, four factors were listed as the possible cause of the U.S. weight problem. These factors and the percentage of those surveyed who considered them an important cause are:

• Failure to get exercise enough—75%
• Lack of willpower on what to eat—59%
• Kinds of foods marketed in restaurants and grocery stores—50%
• Effects of genetics and heredity—32%

Source: “Americans See Weight Problems Everywhere but in the Mirror,” April 11, 2006, Pew Research Center.