Suppose you were asked to classify your weight as either underweight,
healthy weight, overweight, or obese. Do you think your assessment
of your weight category would square with that of public health
officials?
If it does, you are more realistic than many of us. According
to a recent ERS analysis based on 1994-96 data, many American adults
misidentify their weight category. Forty-one percent of individuals
whom health professionals would classify as overweight, but not
obese, did not perceive themselves to be overweight. Among those
individuals whom professionals would classify as obese, 13 percent
said that their weight is about right or even too low.
ERS researchers used self-reported heights and weights to calculate
survey respondents’ Body Mass Indices (BMI—weight in
kilograms divided by height in meters squared). Adults with a BMI
of 30 or above are classified as obese by public health officials.
Those with BMIs at or above 25 but less than 30 are classified
as overweight. ERS researchers gleaned respondents’ perceptions
of their own weight category by their answer to the survey question:
Do you consider yourself to be overweight, underweight, or about
right?
Why would economists be interested in a potential mismatch between
individuals’ perceptions of their weight category and official
classifications? It often falls to economists to determine the
cost-effectiveness of potential government programs, such as public
information campaigns. This research suggests that designing a
campaign to combat overweight and obesity may be difficult because
the public may need to be educated not only about the linkage between
weight and health, but also about whether they are considered overweight
or not.
The design of information programs may be further complicated
by the finding that misperceptions of weight category appear to
vary by gender and other demographic characteristics. For example,
women who were overweight or obese according to official measures
were more likely to say they are overweight than men—41 percent
of women respondents versus 35 percent of men. Fourteen percent
of women respondents (versus 4 percent of men) perceived themselves
as overweight when they were not. Individuals who were overweight
or obese and perceived themselves to be a healthy weight were more
likely to be non-Hispanic Black or Hispanic than Asian or non-Hispanic
White. ERS researchers found that accuracy in assessing weight
category also varies with education, age, income, and diet and
health knowledge.