The obesity rate in the United States declined slightly in 2011, in contrast to rising levels found in 2009 and throughout most of 2010, according to a new Gallup poll.

The percentage of "overweight" or "obese" people in U.S. declined during the third quarter of 2011. The percentage of obese Americans is down to 25.8 percent from 26.6 percent last year and the percentage of Americans overweight is 35.8 compared with 36.0 percent a year ago.

However, the majority of Americans are still at an unhealthy weight -- either overweight or obese (61.6 percent), according to the poll results.

On the other hand, normal weight people increased to 36.6 percent in the third quarter of 2011, compared with 35.6 percent last year.

"Though it is noteworthy that more adults are now a normal weight than overweight, it is too early to tell if this shift is temporary or permanent," Gallup noted.

The study noted that tough economic times could be one of the reasons for the rate change as Americans likely chose to eat at home than eating at restaurants with meals high in calories.

But it also noted that the middle-aged, black Americans, and low income people the most likely to be obese across major demographic subgroups, the survey found.

The Gallup-Healthways Well-Being Index uses respondents' self-reports of their height and weight to calculate body mass index scores. It has monitored Americans' weight situation daily since January 2008.