Ninety percent of Americans know that most of their compatriots are overweight, but just 40 percent believe themselves to be too fat, according to a study published Tuesday.
Government statistics show that more than 60 percent of the U.S. population is overweight, and half is obese, meaning they are at serious risk of health effects from their weight.
But the Pew Research Center telephone survey of more than 2,000 adults found that many people overestimate how tall they are and underestimate how much they weigh — and thus do not rate themselves as overweight, even when they are.
"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," Pew says in the report, published on the Internet.
"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."
Americans giving up on diets?
And at least some people appear to have given up on dieting to control their weight, the survey found.
"One in four respondents in our survey say they are currently dieting, and roughly half (52 percent) say they have dieted at some point in their lives. In a poll taken 15 years ago, the percentage of adults who reported having ever dieted was slightly higher — 57 percent," the report reads.
The adults polled were asked how tall they are and how much they weigh. Doctors and researchers around the world use a ration of height to weight called body mass index to calculate if someone is obese or overweight.
The women reported they weighed a median of 150 pounds and had a median height of 5 feet five inches, which would put them just barely on the borderline of being overweight.
But national statistics indicate that U.S. women in fact have a median weight of 155 pounds and are only 5 feet 4 inches tall, which puts them squarely into the overweight column.
"As for men, well, they give themselves even more phantom height than women do — two extra inches," the report reads. "The self-reported median height of men in the Pew survey is 5 feet 11 inches, compared with 5 feet 9 inches in the government survey."
Those surveyed agreed that maintaining a healthy weight is important.
"Virtually everyone agrees that a person's weight has an impact on the chances for a long and healthy life," the report reads.
"More than nine-in-ten (91 percent) believe that weight has an impact on attractiveness, either a little (35 percent) or a lot (56 percent)."