Soda sales are down, which could signal a healthy change. (Image credit: Justin Sullivan/Getty Images)

Great news: We're buying less soda. Coca-Cola, PepsiCo Inc. and Dr. Pepper all reported declines in soda sales during the second quarter in North America despite new marketing efforts.

Why is this a good thing? Because sodas and other sugary drinks are linked to one of the biggest public health crises of our lifetimes: obesity.

25,000 Deaths Tied to Sugary Drinks

The decline is just the boost I needed to help take the sting out of what I saw near my office a couple weeks ago. I was just walking out of our building when I was greeted by an incredibly enthusiastic group of young people.

"Hey, mister," one of them said. "Want a free can of Shaq soda?"

I looked at the smiling face of Shaquille O'Neal beaming on the side of each massive can.

"No, thanks. Not interested," I replied.

"But it's free!"

Really? Free? The new cream soda made by Arizona Beverages comes in a massive 23.5-ounce can containing the equivalent of 17 teaspoons of sugar amounting to 270 calories. Nothing free about that. That's a ton of sugar.

Tips for Cutting Sugar From Your Daily Diet

My first health tip to all of my patients regardless of their age or weight is to stop drinking sodas, sports drinks and other sugary beverages. It's one of the simplest things that they can do for their health.

To help drive home the point, I keep a clear plastic soda bottle containing white crystals on my desk (it's actually salt, but you get the idea). When I ask people to guess how much sugar is in a bottle of soda, no one has come close to being correct. Their eyes widen and they gasp when I tell them that the 20-ounce bottle of soda they drink contains 17 teaspoons of sugar.

Roughly half of all Americans consume a sugary drink every day, according to the U.S. Centers for Disease Control and Prevention. Among those younger than 20, 70 percent of males and 60 percent of females have at least one. That's a lot of soda! It's easy to see why, given advertising campaigns directed right at them. Start them young and they will be customers for life.

Now add Shaq to the list of celebrities who have sold unhealthy drinks: Beyonce, Elton John, David Bekham, One Direction, Madonna…. The list goes on and on. All saw fit to put their faces and names behind selling soda. Hopefully, one day, selling sodas to kids will carry the same stigma as selling cigarettes.

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But it does seem like the anti-soda message is getting out. Sales are going down, not up. I like to think that efforts in places like New York City to limit the size of sodas that could be sold has raised awareness of the dangers of sugary drinks. It takes bold campaigns like that to counter the massive money that is spent to sell unhealthy drinks to our children.