A group of doctors, nutritionists, and economists says a penny per ounce tax on sugary drinks could raise almost $15 billion a year for health programs.

"It's only fair that people consuming these beverages help share the cost of the diseases that they're putting upon themselves," said the report's author, Dr. Walter Willett of the Harvard School of Public Health.

The question is whether these sugar-sweetened beverages really are to blame for diabetes, heart disease, and obesity. Some studies say yes. Others say no.

An author of the popular "You" health guides says we need an answer.

"There have not been the randomized studies to show -- and that have shown definitely -- that cutting these out makes a huge difference," said Dr. Michael Roizen.

Take Arkansas and West Virginia, for example. The beverage industry says they have sugar taxes and also some of the highest obesity rates in the country.

"The sale of regular soft drinks has been going down over the last 10 years by 9 percent. At the same time, the obesity rate has been rising. So I don't see the correllary," said Susan Neely, a spokeswoman for the American Beverage Association.

Experts pushing the sugar tax believe it'll cut consumption by 8 percent, just as cigarette taxes led to fewer smokers. It would be levied on manufacturers, not directly on consumers. It would be an incentive, they say, for producers to cut the sugar.

"If they cut out 10, 20, 30, 40 percent of the sugar in those beverages, that would be wonderful. We would love that. That would be a victory," said Barry Popkin, an economist and representative with the UNC Interdisciplinary Obesity Center.

The beverage industry insists there are already plenty of choices. Just Wednesday, for example, a European firm is pitching a new guide, teaching beverage-makers how to better market healthy beverages to children.