Does soda cause obesity? Does it weaken bones? Experts bust eight popular myths

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Do sugary drinks cause obesity? State Supreme Court Justice Milton Tingling, who recently dismissed New York City's proposed "soda ban," isn't convinced. As Huffington Post Healthy Living editor Meredith Melnick reports, Tingling made clear that the city's Board of Health was only meant to intervene "when the city is facing eminent danger due to disease," he wrote in the decision. "That has not been demonstrated herein."

To us, the case is pretty clear: Sugary beverages are not just loaded with calories, they also seem to trigger the genes that predispose some of us to weight gain, according to 2012 research.

But a number of other lingering questions about soda and our health are less black and white: Is diet soda any better for us? Do the bubbles affect our bones? And what about high fructose corn syrup? Here are the facts behind some of the biggest claims made about sugary drinks and our health.

1. The claim: Diet soda is better for you than regular soda

The reality: "Diet soda is no panacea," says Lisa R. Young, Ph.D., R.D., C.D.N., adjunct professor of nutrition at NYU, author of The Portion Teller Plan. Sugar-free doesn't mean healthy. In fact, the "false sweetness" of diet soda can be quite problematic, says Young. The theory goes that the brain thinks that sweetness signals calories are on their way, and triggers certain metabolic processes that could, in fact, lead to weight gain in diet soda drinkers.

And widening waistlines aren't the only downside: diet soda has been linked to a whole host of health problems, including increased diabetes, stroke, and heart attack risk.

These studies don't necessarily prove that drinking diet soda regularly causes health problems, Young cautions, but there's certainly nothing nutritious about it.

RELATED: Slash calories and sugar, not flavor, with these skinny margarita recipes.

2. The claim: If you want a big boost of energy, choose an energy drink over coffee

The reality: The truth is, a soft drink marketed for energy-such as Red Bull or Rock Star-contains less caffeine than a cup of coffee, but more sugar. Sure, an energy drink is easier to chug, but that doesn't change the simple fact that your average brewed coffee has between 95 and 200mg of caffeine per eight ounces, while Red Bull has about 80 mg for 8.4 ounces, according to the Mayo Clinic.

3. The claim: Clear soda is healthier than brown soda

The reality: While the caramel coloring responsible for that brown hue can discolor your teeth, says Young, the big difference between clear or light-colored sodas versus darker sugary drinks is typically caffeine. Think Coca Cola versus Sprite, or Pepsi versus Sierra Mist. (Mountain Dew is the obvious exception.) Considering that the average can of soda has less caffeine that a cup of coffee, most soda drinkers probably don't have to swap Coke for Sprite. But if you are nearing the "how much is too much?" caffeine tipping point, this might actually be a good rule of thumb to follow.

4. The claim: Soda made with corn syrup is worse than soda made with cane sugar

The reality: It turns out that the problem isn't necessarily the corn-derived sweetener, it's the fact that the sugar is in liquid form. "I've done a lot to demonize it," Michael Pollan famously told the Cleveland Plain-Dealer. "And people took away the message that there was something intrinsically wrong with it. A lot of research says this isn't the case. But there is a problem with how much total sugar we consume."

Both full-calorie sweeteners break down into approximately half glucose and half fructose (corn syrup is about 45 to 55 percent fructose, compared to sugar's 50 percent). As such, they behave very similarly in the body, which is to say dangerously: "HFCS is, of course, 45-55 percent fructose, and liquid cane sugar is 50 percent fructose," says David Katz, M.D. and director of the Yale University Prevention Research Center. "So they are compositionally all but identical. Sugar is sugar, and the dose makes the poison in either case."

5. The claim: A trip to the gym warrants a sports drink

The reality: Watch a Gatorade commercial and you're apt to think you'll need a sports drink anytime you break a sweat. But the truth is that your electrolyte and glycogen reserves aren't depleted until more than an hour of intensive training. So that 45-minute session on the treadmill? Probably not going to require much more than some water.

6. The claim: Carbonation weakens bones

The reality: Young says this claim was likely born of the idea that if kids (or adults, for that matter) are drinking more soda, they're drinking less bone-benefitting milk. But recent research has zeroed in on the soda and bone density link. A 2006 study found that women who drank three or more colas a week (whether they were diet, regular, or caffeine-free) had significantly lower bone density, leading researchers to believe the culprit is flavor agent phosphoric acid, found more often in colas than clear sodas, that ups the acidity of the blood, The Daily Beast reports. The body then "leaches some calcium out of your bones to neutralize the acid," study author Katherine Tucker told the site.

Others have suggested that it's simply the carbonation that hurts bones, but the effect from a single soda would be negligible, according to a report by Popular Science.

RELATED: Soda's not the only food you should stay away from! Avoid these nine common foods with toxic ingredients.

7. The claim: All calories are the same, no matter their source

The reality: Research suggests that rapid consumption of the fructose in both sugar and high fructose corn syrup doesn't properly stimulate production of leptin, a hormone that sends the brain a signal when the body is satiated. This commonly leads to overconsumption of the highly caloric drinks. And research finds that soda drinkers do not compensate for their extra calories by eating fewer calories elsewhere. In other words: you're probably going to eat some fries with that soda-not an apple.

8. The claim: Mountain Dew lowers sperm count

The reality: This myth is little more than urban legend. No research exists documenting any effect on fertility from drinking Mountain Dew, Everyday Health reports. Many speculators link the rumor to the (deemed-safe) food coloring Yellow No. 5 that gives Mountain Dew its neon hue. Yellow No. 5 has made headlines recently, as one of two food dyes two North Carolina bloggers seek to eliminate from Kraft Macaroni & Cheese. They claim Yellow No 5 is dangerous, and in fact the food dye has been linked to conditions such as allergies, ADHD, migraines, and cancer.

"At the end of the day, it's all about moderation," says Young. "Nobody's going to have a reduced sperm count from the occasional soda."

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