There has been some talk around the office that Coke Zero is not only bad for you, but addictive as well. As someone who typically consumes three liters of the stuff every week and isn't trained at all in medicine or biological chemistry, I think I can speak with a little authority when I say that Coke Zero is not only not addictive, but it's not not addictive.
Coke Zero was introduced to me several years ago by a co-worker who extolled its taste. At the time I was not interested in any soda aside from the occasional C.C. Lemon or rare can of Dr. Pepper. However, after throwing caution to the wind I tried the black drink and found that I liked it ... a lot. From that point on, I would have at least one bottle every week. While working in Tokyo I'd often have one or two bottles of the drink every day and, now that I'm back in Nagoya, I limit myself to just three cans a week1. Although I will admit that there are times when I would love to have a Coke Zero on the weekend, I cannot bring myself to claim that this stuff is any more addictive than real coffee.
Soda has caffeine, and Coke Zero is no different. Caffeine is addictive. When our brains run low on the stuff, some people feel tired, others angry, some think they're falling into some sort of diabetic shock. A quick recharge later, and everything is back to normal. Does this mean that Coke Zero is addictive? Hardly. But why is it that when people drink this particular soda they claim an inability to stop?
It tastes good. Seriously. Coke Zero is perhaps the best-tasting soda I've had in years, which is why I reach for it given the opportunity ... and there's a lot of opportunity in a country where vending machines stand in the middle of nowhere surrounded by several kilometers of rice fields.
Another reason people might feel that Coke Zero is addictive is related to the non-sugar sweetening agent Aspartame. Aspartame is an artificial sweetener that's known to have several rather negative side-effects when consumed excessively. One little-known fact about aspartame, though, is that many people feel the need to have something sweet after consuming a bit of the product. As an artificial sweetener, the body is expecting something that it never receives, so the brain says "Hey, I'd like some more of this", which doesn't really help matters. So it's no surprise that people feel thirsty for something sweet after drinking this product. And when we're thirsty what will we reach for? Another bottle of Coke Zero.
If Pepsi made a product that tasted as good as this, this post would be talking about more than one soda that people claim is addictive. Instead there's just one product that seems like a great mix for adult tongues around the world, and it happens to be a Coca-Cola product.
Still ... it's interesting to hear people with all sorts of strange theories talk about this product like it's some secret project to control people.