Is American obesity rate on the decline? Survey reports encouraging

By Dr. Ananya Mandal, MDOct 10 2011

Results of a Gallup Poll released Friday reveals that obesity rates among Americans may have decreased, albeit slightly.

Latest findings showed that for the first time “normal” beat out “overweight.” The survey however found that 61.6% of Americans were in the categories of either “overweight” or “obese”. The survey found 35.8 percent of Americans to be overweight, compared with 36.0 percent a year ago, and 25.8 percent obese, down from 26.6 percent last year.

First Lady Michelle Obama has made fighting childhood obesity and promoting healthful eating her priorities. Denmark has imposed a tax on saturated fats and foods containing them, and other European governments are studying a similar tax, as a way of forcing people to reduce weight, which is necessary to cut healthcare costs.

The latest survey findings are encouraging, but it's unclear whether they are a trend or just temporary. There is also the problem, inherent in all survey data but especially acute in this subject area, about whether respondents are telling the truth.

The latest survey is based on respondents’ reports of their weight and height, which are then used to calculate their body mass index (BMI) scores. Individual BMI values of 30 or higher are classified as “obese,” 25.0 to 29.9 are “overweight,” 18.5 to 24.9 are “normal weight,” and 18.4 or less are “underweight.”

African Americans, the middle-aged and those with low incomes continue to be the groups most likely to be obese or overweight, according to the survey data, which cover three quarters of 2011. Those with annual incomes of $36,000 to $89,999 had the biggest drop in obesity, a full percentage point from 2008. Asians showed the biggest gain, 3.3 percentage points, in obesity from 2008.

A downward trend in obesity rates could also mean a drop in U.S. healthcare costs, the study said. The Centers for Disease Control and Prevention estimated medical costs associated with obesity were $147 billion in 2008.

Survey results are based on telephone interviews from July 1 to Sept. 30, using a random sample of 90,070 adults, and a similar number in previous quarters. The overall margin of error is plus or minus one percentage point, though the margin of error increases among the subgroups to a maximum of plus or minus 3.5 percentage points.