Recent studies that cast doubt on the benefits of diet soda and suggest consuming pop can lead to aggression in children come at a time when major soft-drink manufacturers are waging a controversial marketing battle to put a healthy spin on sugar-sweetened beverages.

One of the most proactive is Coca-Cola, which produced ads earlier this year that tout how easy it is to work off the calories in a serving of Coke. A version that aired in the United Kingdom was banned in July by authorities who said it misled consumers.

Canadian obesity expert Yoni Freedhoff says the emphasis on health is "deceptive" and signals a last, desperate attempt to legitimize an industry that is increasingly viewed as a health risk.

"I do think that the writing is on the wall," says the founder of Ottawa's Bariatric Medical Institute and an authority on weight issues. "I don't think there's anything more clear-cut as not good for people, in my mind, than sugar-sweetened beverages. There's nothing nutritionally beneficial about them.

"I think that this really is the Big Tobacco playbook that

[soft-drink producers are] playing from."

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A controversial New York City department of health ad that was part of a campaign to limit the size of sodas that could be served in restaurants and other facilities. (Reuters)

Freedhoff is referring to an influential paper published in 2009 called The Perils of Ignoring History: Big Tobacco Played Dirty and Millions Died. How Similar Is Big Food?

Written by two obesity researchers — Yale University's Kelly Brownell and Kenneth Warner from the University of Michigan — the paper says that after studies began linking smoking to lung cancer in the 1950s, the cigarette industry stressed the importance of the public’s health and promised a number of "good-faith changes."

What followed, say Brownell and Warner, was a prolonged marketing "playbook" that emphasized personal responsibility, paid scientists to deliver dubious research and criticized any science that suggested harms associated with smoking, among other tactics.

David Moran, director of sustainability at Coca-Cola Canada, calls the comparison "unfair and not accurate."

"There's no way that you can consume tobacco in any way that's healthy," says Moran. "But with our products, you can consume them in a healthy, active lifestyle."

Making connections with good health

For a number of years, medical experts have cited soft drinks as one of the leading causes of obesity, diabetes and heart disease.

In June, a study from Purdue University in Indiana suggested that despite their low calories and sugar content, diet soft drinks can still contribute to weight gain and diabetes.

Meanwhile, a U.S. study of preschoolers released on Aug. 16 reported that consuming several servings of pop a day is associated with behaviour problems such as aggression.

At the same time, soft drink manufacturers have in recent years introduced products that advertise nutritional benefits.

In the mid-2000s, Coca-Cola brought out Diet Coke Plus, which the company described as "Diet Coke with Vitamins and Minerals." In 2009, the Dr Pepper Snapple Group introduced a line of 7Up flavours said to contain antioxidants.

In 2008, however, the U.S. Food and Drug Administration ruled that Diet Coke Plus made improper nutritional claims; the drink has since been discontinued in the U.S.

In July, the Dr Pepper Snapple Group agreed to stop fortifying its 7Up drinks with vitamins and claiming they contain antioxidants, after a California consumer filed a federal class action lawsuit.

According to the complaint, the packaging of 7Up varieties such as regular and diet Cherry Antioxidant and Mixed Berry Antioxidant suggested the antioxidant came from fruit, when in fact there is no fruit content in 7Up.

Fighting obesity

Coke's Moran says the marketing approach is slightly different in Canada, because Health Canada has strong restrictions on touting the nutritional value of soft drinks.

Even so, beverage makers have taken a pro-active stance in the fight against obesity. Earlier this year, Coca-Cola Canada launched a campaign called "Coming Together," which aims to raise awareness of ways to reduce weight gain.

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Not everyone liked N.Y. Mayor Michael Bloomberg's campaign to limit soft-drink sizes, including a judge who quashed the city law earlier this year. (Kathy Willens / Associated Press)

The company also renewed a partnership with ParticipAction, the national not-for-profit that promotes physical activity.

"Our focus has been a lot on calorie awareness," says Moran, who emphasizes that Coca-Cola also produces lower-calorie products, such as diet drinks and flavoured waters.

Part of the "Coming Together" campaign is an ad called "The Calorie Dictionary," which suggests some simple ways a person could work off the 160 calories in a 13.5-ounce bottle of Coke, including five minutes of skateboarding (45 calories), yelling (13 calories) or demolition work (39 calories).

Freedhoff says the ad is "purposely deceptive," saying it's unclear in the commercial that a person would have to complete a combination of these activities — not just one of them — to work off the serving of Coke.

He adds that diet is much more important than exercise in determining weight gain.

But not everyone is opposed to the ad campaign.

"Healthy living is the issue here, and so calorie-counting is a part of that, and certainly if you start drinking the Big Gulps, your toll is going to go up very quickly," says Michael Mulvey, a marketing professor at the University of Ottawa.

"At least [Coke is] initiating a dialogue — they're showing a partial solution to the problem. In a way, it is offering some balance to the other array of ads that they have that say this is a pause that refreshes or this is a treat or this is a bonding experience."

The art of 'health-haloing'

Claire Tsai, a marketing expert at the Rotman School of Management, concedes that some of the anti-soft drink rhetoric nowadays compares it to cigarettes, but she says there is a critical distinction between the two products.

"The biggest difference between soft drinks and tobacco is that tobacco is linked with lung cancer, a fatal disease, while obesity is linked with other fatal diseases, but it’s not the only thing that causes those fatal diseases," she says.

"So it's unlikely that we’ll see a class-action lawsuit in the context of soft drinks."

Mulvey adds that "with tobacco, a lot of [the criticism] has been motivated by secondary smoke and all the people that didn't have the choice" in consuming it.

Freedhoff says Coke, like many food and beverage manufacturers, is simply engaging in "health-haloing," a marketing practice in which companies create associations between their products and healthy living.

"These are incredibly savvy marketers, incredibly savvy sales people," says Freedhoff.

"Not having these ads would be better than having them, but [they]

are a lesser evil than further vilification of soft drinks by the public and by public health officials."