Oct. 16 (HealthDay News) -- Current state taxes and levies on soft drinks are slowing consumption, but not enough to curb the obesity epidemic in the United States, researchers say.

In an analysis of 16 years of data (1990 to 2006) on how various forms of soft drink taxation affected body mass index, researchers found that taxation has only a minor effect on BMI, which is a measurement based on weight and height. For example, a 1 percent tax increase causes a BMI decrease of 0.003 points -- less than a tenth of a pound for a man of average height.

Soft drink taxation had the most BMI impact among people with lower incomes, females, and middle-aged and older people. But even in these groups, the effects on obesity were very small, according to the study findings released online Oct. 15 in advance of publication in an upcoming print issue of the journal Contemporary Economic Policy.

"Our results suggest that the current low, hidden rates of soft drink taxation in most states are not effective in substantially changing adult consumption," study author Jason M. Fletcher, an assistant professor at the Yale School of Public Health in New Haven, Conn., said in a university news release. "Our results leave open the possibility that large taxes that are communicated to consumers are still worthwhile to consider as policy options, but small tax changes will not work."

Currently, the average tax rate on soft drinks is about 3 percent, but a number of states are considering increasing that rate.

SOURCE: Yale University, news release, Oct. 16, 2009