Updated

You drink diet soda, so you must be healthier. Right?

That's what New York Gov. David Paterson is talking about with his proposal for an "obesity tax" — a 15 percent slap on non-diet sugary soft drinks. Think $1 for a Diet Coke, $1.15 for a Coke.

There's just one problem: Studies have found links between drinking diet sodas and obesity and diabetes.

A 2005 study at the University of Texas Health Science Center, San Antonio, and separate studies released in 2007 at the University of Alberta in Canada and the University of Massachusetts found that diet soda drinkers were more likely than regular soda drinkers to be obese.

Also, several studies by U.S. and European researchers have tied the artificial sweetener aspartame (NutraSweet), which is used to sweeten many diet sodas, to cancer, headaches and organ damage -- though both the U.S. Food and Drug Administration and the European Union maintain that the studies they’ve reviewed show that the product is safe.

According to Paterson's proposal, the obesity tax would net an extra $404 million a year for the state and help close its projected $15 billion deficit.

In addition to soda, sugary drinks containing less than 70 percent fruit juice would be subject to the tax, a spokeswoman for the governor told FOXNews.com.

Milk, juice, diet soda and bottled water would not be subjected to the tax. The governor’s plan is on par with the so-called fat tax movement that has been touted by some health experts, but has failed to gain favor with political officials thus far.

Much like the cigarette taxes that have taken shape in some states in recent years, a fat tax would capitalize on — some would say punish — people’s unhealthy lifestyle choices.

“It should be taxed, in fact there should be a federal tax on it,” said Dr. Carla Wolper, a nutrionist and registered dietitian with St. Luke’s Hospital Obesity Research Center in New York City. “Obesity is such a serious health problem and it’s something that can be controlled. So I say, absolutely, tax it.”

In addition, Paterson spokeswoman Erin Duggan said in an e-mail to FOXNews.com, the "revenue collected from this tax will be directed to health care initiatives."

State Comptroller Thomas P. DiNapoli estimates that obesity costs New York $242 million a year in public and private medical expenses. Across the state, 1 in 4 children is obese.

But others say the tax is misguided.

In a statement e-mailed to FOXNews.com, the American Beverage Association, the trade group that represents the soft drink industry, called Paterson's proposal a “money grab” and said the governor is unfairly singling soda out as the main culprit for obesity.

“The governor’s rationale for the tax is flawed,” the beverage association said in its statement. “It makes no sense to single out one food product as the cause for obesity. There is no science or logic that justifies it. Rather, we need to focus on promoting balanced eating habits and more physical activity. Until we get our kids exercising more the scales will be tipped against our next generation.”

A spokeswoman for Pepsi Cola referred inquiries to the beverage association, which is speaking on its behalf; Coca-Cola did not return calls from FOXNews.com.

Wolper said she disagrees with the diet soda research, but she warned that drinking juice is just as bad for the belly and the thighs and the hips as drinking soda.

“Fruit juice has exactly the same number of calories as soda, so if you give up soda and start drinking fruit juice in its place, you’ll lose no weight,” she said. “I hear it from patients all the time. They’ll say, ‘I gave up soda, but I’m not losing weight.’ And when I ask what they’ve replaced it with, it’s usually fruit juice.”

Wolper also agreed that junk food like potato chips, cookies and candy also contribute to the obesity epidemic, but she said taxing food could be difficult due to the food industry’s powerful lobbying groups.

“But then again, the cigarette lobby is very powerful too, and they were eventually able to tax them,” she said. “And by taxing cigarettes, we’re preventing young people from starting smoking.”

As for the argument that the sugar found in regular soda is somehow better for people than the artificial sweeteners found in diet drinks, Wolper said there is no scientific evidence that points to that.

“Soda offers no nutritional value,” she added. “It’s empty calories. There’s nothing in it that you need to stay healthy.”