The Taste Of Coke Is All In Your Head

I’m a big fan of Mexican Coke. I can bore you silly talking about the elegant slender glass bottle, and the simple sweet taste of real sugar (Mexican Coke is made with sucrose, not high-fructose corn syrup) and the slightly lower levels of carbonation. It’s a delicious drink, far less harsh and cloying that its […]

I'm a big fan of Mexican Coke. I can bore you silly talking about the elegant slender glass bottle, and the simple sweet taste of real sugar (Mexican Coke is made with sucrose, not high-fructose corn syrup) and the slightly lower levels of carbonation. It's a delicious drink, far less harsh and cloying that its American equivalent. (And did I mention the glass bottle? And the cool "Hecho in Mexico" sticker?)

But here's the rub: Mexican Coke appears to be a cognitive illusion. Marion Nestle summarizes a recent study in Obesity:

You know how everyone thinks Mexican Coca-Cola is so much more delicious than American Coke because it is made with table sugar (sucrose), not HFCS? Oops again. The investigators could not find any sucrose in the Coke, but did find plenty of glucose and fructose. This suggests that Mexican Coke is also made with HFCS (or it could also mean that the sucrose had been split into its constituent glucose and fructose).

To review the biochemistry: Sucrose is a double sugar of glucose and fructose bonded together. HFCS is glucose and fructose, separated. The sucrose bond is quickly split in the intestine and its glucose and fructose are the same as those in HFCS.

I'll begin with a defense of my tongue, before I explain before why my tongue is probably wrong. Although the researchers conclude that Mexican Coke is probably engaging in deceptive labeling (Red Bull and Vitamin Water also have some explaining to do), there are a few possibilities that could also explain the lab results. As Nestle notes, the sucrose could have been chemically split, or it could have been naturally separated by the carbonic acid in the bottle. Who knows? I'd like to focus instead on a chart in the paper that documented the average deviation between actual sugar content and the sugar content listed on the packaging. It turns out that, in many instances, there's a ridiculous level of variation. For instance, "Coke from McDonalds" contained nearly 30 percent more sugar than advertised; Sprite from Burger King contained more than 20 percent additional sweetener. A jug of Hawaiian Fruit Punch Fruit Juicy Red was about 5 percent higher, while bottled Mexican Coke was about 5 percent lower. (It was also about 5 percent lower than American Coke.) So perhaps there is a taste difference. Perhaps the difference is simply that Mexican Coke is less insanely sweet. Maybe I'm not just another annoying hipster.

Or maybe I am. Although I can rationalize away that closet full of Mexican Coke bottles (thank you, Costco!), the psychology of taste perception suggests those rationalizations are wrong. Consider this clever study of soft drinks led by Samuel McClure and Read Montague. The experiment was a recreation of the Pepsi Challenge, except this time all the tasting was being done in a brain scanner. Each person swallowed sips of cola from a plastic tube while their brain was being scanned. When Coke and Pepsi were offered unlabeled, the subjects showed no measurable preference for either brand. Most of the time, they couldn't even tell the two colas apart. But Montague's second observation was more surprising: subjects overwhelmingly preferred drinks that were labeled as Coke, no matter what cola was actually delivered through the tubes. In other words, brand trumped taste. We cared more about the logo than the actual product.

But what was happening inside the brain? When the two soft drinks were offered unlabeled, the dopamine reward pathway became active. This makes sense: the pathway helps processes appetitive rewards, like sugary drinks, which provide us with a rush of sweet pleasure. However, when the subjects drank a cola with a Coke label, an additional set of brain areas became extremely active. The DLPFC, hippocampus and our midbrain emotional areas reacted strongly to the red cursive of Coke, but not to the blue Pepsi logo. (This happened even when subjects were given Pepsi with a Coke label.) For whatever reason, certain brand names are able to excite our nostalgic emotions, and those emotions influence our preference. (The scientists argue that the hippocampal activation is a sign that we're accessing these commercial memories.) The end result is a strong preference for Coke, even though it tastes identical to Pepsi.

Why does Coke trigger our emotions? As the scientists note, Coca-Cola is "advertising incarnate." The company was the first sponsor of the Olympic Games, gave its cola free to U.S. soldiers during World War II, and is credited with inventing the modern image of Santa Claus. Despite the fact that Coke is the most widely recognized consumer product in the world, the brand is still supported by more than $1 billion worth of advertising every year. Whether it's animated images of a penguin family, or inspirational shots of a high-school football game, Coke ads are designed to trigger these remembered feelings of warmth and nostalgia. They are sentimental, not informative.

Mexican Coke has become my Coke. I see that glass bottle and I'm flooded with all sorts of dopaminergic associations, those smug feelings reminding me that I don't drink that generic high-fructose corn syrup crap. I drink the real stuff, the cola made with old-fashioned sugar. But those associations are almost certainly an illusion - my tongue is too crude a sensory device to parse the difference between Coke and Pepsi, let alone between slightly different formulations of the exact same drink. The most convincing evidence comes from Coke itself. Last year, Rob Walker asked the company about regional variations in its ingredients:

It is true, acknowledges a Coke spokesman, Scott Williamson, that different sweeteners are used by the company’s bottling partners in different parts of the world, for reasons having to do with price and availability. But, he says, “all of our consumer research indicates that from a taste standpoint, the difference is imperceptible.”