A Pew Research Center study (linked to from sycophant) finds a “Lake Wobegon effect” in how Americans perceive obesity:

Americans believe their fellow Americans have gotten fat. They consider this a serious national problem. But when they think about weight, they appear to use different scales for different people.

Nine-in-ten American adults say most of their fellow Americans are overweight. But just seven-in-ten say this about “the people they know.” And just under four-in-ten (39%) say they themselves are overweight.

These sliding assessments are drawn from a Pew Research Center telephone survey conducted from February 8 through March 7 among a randomly selected, representative national sample of 2,250 adults.

The survey finds that most Americans, including those who say they are overweight, agree that personal behavior – rather than genetic disposition or marketing by food companies – is the main reason people are overweight. In particular, the public says that a failure to get enough exercise is the most important reason, followed by a lack of willpower about what to eat. About half the public also says that the kinds of foods marketed at restaurants and grocery stores are a very important cause, and roughly a third say the same about the effect of genetics and heredity.

The report is interesting (although they could do much much better in their data displays). It reminds me of the surveys showing misperception of the populations of ethnic minorities and immigrants.