Answer by Caroline Zelonka, advertising copywriter:
Diet sodas have an image problem, and for good reason. In the beginning, they were a speciality item aimed at people with diabetes. The original formulas used the sweeteners cyclamates and saccharin tasted terrible and were widely considered to be bad for your health. (Indeed, both were banned for a time.) But some people didn't care, because they were more concerned with the calorie count than the taste.
Up until fairly recently in American culture, men didn't diet. I mean, many of them probably did, but it wasn't something that most men would admit to. Dieting for the purpose of losing weight was seen as a uniquely female pastime. And the behaviors around dieting were mainly limited to cutting calories: eating a half grapefruit for breakfast, dry salad with cottage cheese for lunch, maybe a broiled chicken breast and some consommé for dinner. And, of course, drinking "no cal" sodas.
None of this was very manly. Men were expected to exercise, pump iron, maybe drink raw eggs like Rocky Balboa. And they did.
But now I'd argue that dieting and calorie counting has gone mainstream. Heck, so has diabetes.*
And a lot more people who, a generation ago, wouldn't have to worry about their weight or sugar intake are now worried. Diet soda tastes a lot better than it ever did, and there's no reason why men shouldn't be guzzling it in the same quantities as women.
But there's still the image problem. Drinking sugar-free beverages is seen as emasculating. The soda companies tried to market their regular diet beverages to men, but it didn't work. So they found the need to make "male" versions of their popular diet beverages.
Coke Zero was specifically launched to reach the male market. The flavor profile is different. It tastes bolder, less sweet. The can packaging is also different. Diet Coke is light and silvery, but Coke Zero is mostly black. The word diet is nowhere to be seen.
Coke Zero was hugely successful. Dr. Pepper co-opted this strategy, a little ham-handedly in my opinion. ("Not for women" belongs on a strategic brief, not on a creative advertisement.) But, eh, they don't have the creative vision—and likely, the marketing budget—to do subtle. The fact that this Dr. Pepper has 10 token calories is a nice touch. Not enough to matter, but enough to place it firmly away from the "no cal" label and all the emasculating baggage it contains.
*In 2011, almost 26 million Americans have diabetes; that's 8.3 percent of the population. And a whopping 79 million have pre-diabetes. Almost all of these cases are Type 2 (formerly called adult-onset), which can be triggered by obesity.
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