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Today in Your Health, the teenage brain - which is not as bad as you may think. First, the fuel on which many American brains run, for better or worse - soda. Seems more Americans have gotten the message that sugary drinks are doing their waist lines no favors. As more people cut back, there's been a steady rise in consumption of diet soda. NPR's Allison Aubrey looks at whether swapping one for the other really pays off.
ALLISON AUBREY, BYLINE: If you focused on changing just one thing, one strategy in your diet in order to move the needle on the scale, what would it be?
CARLETTA GIRMA: For me it would be I would stop eating junk food at my desk at work.
AUBREY: Junk food, like what? Chips, soda?
GIRMA: Chips. Chips.
AUBREY: That's Carletta Girma, who was eating lunch out with her friend Julie Ost.
JULIE OST: We were just talking about this. I was talking about the candy bowl at work. I know where two candy bowls are at work, so that would probably be the elimination.
AUBREY: Not a bad strategy. Those would be empty calories. But interestingly, neither mentioned all the liquid calories they consume each day. Carletta says she's addicted to caramel sweetened coffees and when it comes to soft drinks?
GIRMA: If I drink a soda, I drink the real deal - Coke. I feel like if you're going to go for it, go for it.
AUBREY: So I asked Carletta what if there were good reasons to believe that these sugary, liquid calories were particularly significant when it comes to body weight? Would she be willing to listen?
AUBREY: So here's the theory of a lot of experts, including Cara Ebbeling of Harvard Medical School and Boston Children's Hospital.
DR. CARA EBBELING: I think that consumption of sugar sweetened beverages may be a particularly high impact behavior when it comes to controlling body weight.
AUBREY: To test this theory, Ebbeling and her colleagues recently completed a big study designed to measure just this one thing - the influence of sugary drinks.
EBBELING: So we recruited adolescents who were drinking at least one sugar sweetened beverage per day.
AUBREY: All of them were overweight. And for an entire year these teens and their families received home deliveries of diet soda and water, and they were counseled to avoid sugary drinks. At the end of the year, Ebbeling says, these teens who'd been on a trajectory of weight gain had gained significantly less weight compared to a control group of teens, who had continued to drink sugary drinks.
EBBELING: We found that there was a difference of just over four pounds.
AUBREY: Just because of the differences in drinks? Nothing else about their diet, presumably, changed?
EBBELING: That's correct. We did not counsel around anything else.
AUBREY: This is some of the strongest evidence yet that swapping sugary drinks for zero calorie options can influence weight significantly. But there's still some resistance to the idea that diet soda is the healthy option. Friends Carletta and Julie say they're still not ready to switch.
OST: No. No. It's really hard to really understand what it does, physiologically, in the body.
AUBREY: For instance, earlier studies suggested that perhaps drinking diet soda somehow leads people to eat more. And Danish researcher, Bjorn Richelsen, told me the Danes have had the same concern.
BJORN RICHELSEN: We had the idea, for sure, that diet soda would enhance appetite.
AUBREY: But Richelsen says this is not at all what he found when he studied it experimentally. He compared what happened when volunteers drank Diet Coke and when they drank water. He measured how this influenced hunger hormones.
RICHELSEN: We also measured what they were eating four hours after.
AUBREY: And he says, what he found was very surprising. Sugary Coke led people to be slightly hungrier, while Diet Coke had a more neutral effect on appetite. It did not lead people to eat more at the next meal.
RICHELSEN: Our conclusion was quite clear. We found that if you're drinking soft drinks without calories, really, it behaves exactly as drinking water.
DR. ROBERT LUSTING: We're still learning a lot about diet soda.
AUBREY: That's physician Robert Lustig of U.C. San Francisco. He's been pushing for Americans to make drastic cuts in sugar. And he says since drinks in the form of soda, juices and sports drinks account for about a third of sugar we consume, they're the obvious place to start.
LUSTING: If you got rid of 33 percent, you would be knocking our added sugar consumption down from 450 calories a day to 300 calories per day.
AUBREY: And so, he says, if diet soda is the baby step to wean people from sugar, which he argues is habit-forming, maybe that's not a bad thing.
LUSTING: I kind of liken diet soda to methadone.
AUBREY: The drug used to get people off drugs. Not ideal, but perhaps effective. He still thinks drinking water is best, as do all the researchers I interviewed here. And friends Julie Ost and Carletta Girma say, well, maybe.
GIRMA: I could save a lot of money if I just drank water only.
AUBREY: But part of the pleasure of drinking soda is the ritual, she says.
GIRMA: You like to pop the can or open the bottle. You like the sound of the bubbles.
AUBREY: So maybe it needs to be bubbly water.
Allison Aubrey, NPR News.
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