The percentage of Americans of “normal weight” has slightly increased in the past year, but overweight and obese people still command a solid majority, according to a new Gallup Poll survey.

According to the Gallup-Healthways Well-Being Index, 36.6 percent of
Americans are of a normal weight,  compared with 35.8 percent who are
overweight. The trend lines have been playing tag since Healthways began
tracking the fat factor in January 2008, but the latest finding is the
first time “normal” beat out “overweight.”

That's not to say that normal-weight Americans are in the majority,
because there are other categories to be considered.  The survey found
that 61.6 percent of Americans were in the categories of either
“overweight” or “obese,” supplying plenty of fodder for the
multibillion-dollar industry designed to combat fat.

“Although the majority of Americans are still overweight or obese, it is an encouraging sign that obesity rates are trending downward in the U.S.,” the study said.

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.

The study said it was not clear what caused the change, but said it could be due to the tough economy, with cash-strapped Americans choosing to eat in rather than eating at high-calorie restaurants.

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.

The study used self-reported data of height and weight to determine a score of body mass index. It was based on telephone interviews with a random sample of 90,070 people aged 18 and older from July to

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 far too plump, 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.

The study concluded, “Although the majority of Americans are still overweight or obese, it is an encouraging sign that obesity rates are trending downward in the U.S. and among demographic subgroups. Still, future monitoring is needed to determine whether this is a temporary trend.”

Although causes for the recent decline in the percentages of Americans who are overweight and obese are unclear at this point, several possibilities exist: Public awareness and government and business investment in changing Americans' health habits may be playing some role. As obesity and the chronic diseases and healthcare costs that come with it have ballooned, the media, the government, and many businesses have given the issue more attention. During the past year and a half, two major initiatives relating to Americans' health habits have come from Washington. First Lady Michelle Obama launched her anti-obesity Let's Move! campaign in early 2010 — pushing a message about eating better and exercising more and initiating programs to help reach those goals. Separately, the U.S. Department of Agriculture in June 2011 put out a new nutrition icon shaped like a dinner plate emphasizing fruits and vegetables and eating less in general. However, these programs have not been in place for a long time, so it is not possible to determine their effect. At the same time, more businesses are investing in wellness programs for their employees — encouraging good health habits — to reduce healthcare costs.”

Economic conditions could also be related to the decrease in unhealthy weight. Americans continue to spend far less than before the financial crisis and so may be eating at home more and dining out on high-calorie foods less.”

Regardless of the exact cause, if this downward trend continues, it could significantly reduce healthcare costs in the United States, a major portion of which are currently the result of obesity and related preventable chronic conditions.”