Sodas may not sport the obvious dangers (or the kick) that a liter of scotch or a kilo of cocaine represent, but health advocates, researchers, nutritionists and, increasingly, government officials are speaking out ever louder about the perils of consuming too many of these sugary soft drinks.

"It's a lot of calories with no nutritional value that only does bad stuff to your body," said nutrition expert Dr. Donald Hensrud of the Mayo Clinic in Rochester. "There's not much positive to say."

New York City has barred the sale of large-size sodas in restaurants and concession stands. Banned in Boston are full-calorie sodas and soda advertising in city buildings. And it was front-page news when Chicago and San Antonio decided to get some of the nation's first soda machines featuring calorie-count listings as part of an effort to win a $5 million grant from a national beverage lobbying group to reward city workers for living more healthfully.

"The point about sodas is they are an easy target for public health intervention," said Marion Nestle, a nutritionist, New York University professor and influential author of "What to Eat." "All they are is sugar and calories. There's no redeeming feature. The last thing Americans need is extra calories."

Nor, soda's opponents add, do Americans need increased risk of obesity, diabetes, heart disease, tooth decay and other problems.

"People need to step back and look at their health," said Michelle Dudash, an Arizona-based registered dietitian, author and nutritionist. "If you're overweight, cut back on the soda. If you have weak tooth enamel, cut back on the soda. If you have a risk of heart disease, cut back on the soda."

Here are some of the things top nutritionists and dietitians want you to think about next time you're thirsty and reaching for yet another soda or sweet drink:

Swear off the sugar, not the bubbles.

"If you drink one 20-ounce sugar-sweetened beverage a day on top of your regular diet, that would be an extra 250 calories every day," said Andrea Giancoli, a California-based dietitian and spokeswoman for the Academy of Nutrition and Dietetics. "You could gain 26 pounds in a year."

What to do? If it's the bubbles you crave, consider this advice from Lara Ferroni, the Oregon-based author of "Real Snacks: Make Your Favorite Childhood Treats Without All the Junk." She recommends spiking club soda with a few drops of nonalcoholic bitters. These bitters, available in a variety of flavors including orange, lemon and rhubarb even, add flavors without a lot of sugar," she said.

Don't supersize it.

Once upon a time, a 12-ounce serving of soda was considered enough. Now, as Nestle notes, even the "small" soda at the movie theater is pretty darn big.

"People are not getting 20-ounce sodas, they're getting 40-ounce sodas that can have the same amount of calories as a meal," agreed Dudash, author of the upcoming book, "Clean Eating for Busy Families." It's important, she added, to "prioritize" those calories to focus on foods and drinks that provide nutrients, fiber, protein, vitamins.

Think about diabetes and heart disease.

Drinking one or two sugary drinks a day can increase the risk of Type 2 diabetes by 25 percent, according to a 2010 article in the journal Diabetes Care.

The other concern, Giancoli said, is heart disease. Metabolic syndrome, a precursor to heart disease, is a "cluster" of symptoms -- obesity, high blood sugar, hypertension, high triglycerides and low levels of "good" cholesterol -- that can lead to cardiovascular disease and diabetes.

Prevent tooth decay.

Phosphoric acid gives soda that "zippy taste," Dudash said. But that acid can also be corrosive to the protective enamel found on your teeth; decay results.

There are other foods and ingredients, like citrus and citric acid, that also can be hard on the tooth enamel, but Dudash said at least these items offer something in return the body needs, such as fiber, vitamin C or folic acid.

Wean kids off soda.

"Soft drinks of any kind do not belong in young children's diets," said Tina Ruggiero, a registered dietitian in Tierra Verde, Fla. Growing bodies and minds need lots of nutrients, she said, adding, "There's no room for that junk."

At most, Ruggiero said soft drinks could be an "occasional treat" for children between ages 8 and 10. But, she said, it's best not to have soft drinks around at all.

Diet soda doesn't let you off the hook.

Studies are mixed. Some say these drinks may help with weight loss while others claim they can increase the possibility of stroke and metabolic syndrome or even weight gain in some as the brain craves additional sweets.

"Diet soda can be like a nicotine patch -- something to help you get to healthier drinks," said Hensrud, the Mayo expert. "It's not as bad as regular soda, but it's not a good alternative."

Staff writer Warren Wolfe contributed to this article.