It's pretty clear from lots of research that high-sugar drinks are a contributor to the childhood obesity crisis, and that many parents are worried about this. Yet despite some declines, and efforts to curb the size of these liquid candy containers, sales keep bumping along.

According to the Rudd Center for Food Policy and Obesity at the University of Connecticut, sales of sugary drinks totaled $14.3 billion in 2013.

So why is this happening? One reason, the Rudd Center determined in a study released Wednesday, is that clever marketing has parents confused about what is healthful and what isn't.

"All these subtle messages [manufacturers] are giving the consumer are that this is orange juice, or just as good as orange juice," said Jennifer Harris, an associate professor of Allied Health at UConn and one of the new study's authors. "...They never come out and say 'this is a healthy drink,' but...the way it looks, the way it's stocked, the messages on the label" all communicate that the added sugar doesn't matter, she said.

One drink that contains among the highest amounts of sugar and artificial sweeteners is presented to look just like orange juice, she said. It is orange-colored, comes in a clear bottle and is stocked in refrigerated sections of stores, even though it doesn't need to be refrigerated.

[Related: The untold story of how the sugar industry shaped key government research about your teeth]

Writing in the journal Public Health Nutrition, the researchers found that 96 percent of the 982 parents they surveyed online provided their children ages 2 through 17 with sugary drinks over the previous month. On average, they bought drinks from 2.9 of six possible categories -- fruit drinks, soda, sports drinks, flavored water, energy drinks or iced teas. Fruit drinks (77 percent) and soda (62 percent) were the most popular. With few exceptions, more black and Hispanic parents gave their children sugary drinks than white parents did.

When the researchers asked the parents which of these beverages they considered healthful, big majorities cited 100 percent juice and milk (they are, though there is some argument about whether kids need even the sugar provided in 100 percent juice).

Most knew that many of these drinks are not good for their children; only six percent said soda was healthful, for example. But 48 percent said the same about flavored water, 30 percent cited fruit drinks and 27 percent said sports drinks were a healthful alternative. Iced teas, energy drinks, regular soda and diet soda received endorsement by 12 percent or fewer.

The top three brands to get parental approval were Vitamin Water (56 percent), Sunny D (43 percent) and Gatorade (39 percent), though, interestingly, significantly smaller proportions actually provided those drinks to their children.

[Related: Kids who consume energy drinks show hyperactive and inattentive symptoms]

"On-package ingredient claims appear to contribute to common misperceptions about sugary product healthfulness," the researchers wrote. "One-third or more of parents indicated that they specifically look for claims such as ‘low-calorie,’ ‘real/natural,’ ‘vitamin C’ and ‘antioxidants’ when choosing drinks for their children...These claims are most prevalent on packaging for sugary drinks in the categories that parents most often perceive as healthy."

Harris said that "the more health messages on the front of the package, the less healthy the product is. You have to ignore the messages on the front of the package, and if the first ingredient is sugar, put it back."

The researchers also concluded that while parents are concerned about artificial sweeteners, their purchasing habits indicate that some may not realize that the sweeteners and extra sugar are in their children's fruity drinks. And with $784 million spent on ads for sugary drinks in 2010, parents are still buying plenty of soda for children, even though they know it's not healthful, the study reported.

[Related: Does sugar by any other name still taste as sweet?]

Public health advocates have to battle that marketing, Harris said, with continued messages that sugar-added drinks are not good for children, who should be drinking water, low-fat milk and perhaps pure juice in modest amounts.

"I don't think parents are stupid," she said. "I just think they're swayed by the marketing."

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