While Diet Coke launched in 1982, its story begins twenty years earlier.
In 1962, Coca-Cola launched its first diet beverage: Tab (as in “keep tabs on your weight”).
As a health craze took off in the 1970s, Tab became a huge hit.
While original Coca-Cola — full of sugar — owned 60% of the market, the sale of diet drinks where growing 3x faster than the rest of the category.
Coca-Cola execs were concerned that all the brand equity it had built in the name would be lost if Tab became its biggest money maker.
So, in 1980, a secret team within Coca-Cola went to work on Diet Coke.
The drink would cannibalize Tab but the word “Coke” was in the name.
How did Coca-Cola keep the "Coke" brand equity in the name?
There were a few options:
"Sugar-Free" (the name was considered too critical of Original Coke’s key ingredient)
"Light" (competitors already used it)
The final choice: “diet” with a lower case “d”.
Why lower case “d”?
Two reasons:
Execs wanted to de-emphasize “diet” vs. “Coke”
Capital “D” was a noun, which would have conflicted with the Coke trademark (lower case “d” diet is an adjective and no conflict)
Diet Coke’s launch campaign in 1982 didn’t emphasize “diet”.
Rather it emphasized taste. DC was smoother because it had less phosphoric acid (the motto: “Just for the taste it”).
Also, compared to Tab — which targeted the female demographic — Diet Coke had neutral branding.
By the end of 1983, Diet Coke was the most successful diet beverage on the market.
It was the 4th best-selling brand in the beverage category (after Coca-Cola, Pepsi and 7-Up). And from 2011-2015, it overtook Pepsi to be #2 best-seller.
Even with Diet Coke's success, Tab had a good run: it wasn't until 2020 that Coca-Cola discontinued its first diet beverage.
Ultimately, Coca-Cola saw the long term trend and protected its brand by taking a huge risk.
Source: Trung T. Phan, LinkedIn