Proponents of a potential ballot measure to put a once-cent-per-ounce wholesale tax on sugared soft drinks in Multnomah County say the tax will help curb childhood obesity, since studies have conclusively shown drinking sugared beverages increases a child's likelihood of being fat.

But the most recent study to come out of Yale University's Rudd Center for Food Policy and Obesity suggests the tax won't work.

The 2010 study by researchers from Yale, Emory University and Bates College published in the Journal of Public Economics found that a soft drink tax did not decrease childhood obesity at all because kids simply replaced calories from soda with something else. They did buy less soda, but they just drank other high-calorie beverages instead.

Portland physician Greg Coodley, who proposed the measure and has since gained support from Metro District 5 Councilor Rex Burkholder, borrowed the idea from the Rudd Center, which publicly endorsed the concept of a one-cent soft drink tax in 2009 as a way to combat childhood obesity and raise money for public health.

That was before the 2010 study that showed the tax wouldn't actually solve the problem.

However, the researchers did note that children usually replaced calories from soda with healthier drinks, like whole milk, which could make them healthier in other ways, even if it didn't make them lighter.