The Real Story Behind Diet Coke — As Told by the Daughter of the Man Who Launched It

Do you remember your first Diet Coke? I don’t, but I know Coke’s leading role in my life by heart. Like billions of people, I love Diet Coke. Unlike everyone else, I had a front-row seat to its inception, since my father, Sergio Zyman, was a Coca-Cola marketing executive instrumental in the drink’s 1982 launch. My dad has since embarked on a career as a consultant and author of numerous marketing bibles. TIME named him as one of the top three pitchmen of the 20th century. Today, his main job is grandpa and dad, but for two major periods in his life, Coke was it. It’s still part of mine and always will be. 

He started working at Coke in 1979 after being poached from their main competitor, Pepsi-Cola, which he had worked for in New York and Rio de Janeiro, where I was born. Coke was everywhere at my house. My dad’s basement home office resembled an unofficial red and white Coke museum, filled with framed ads and various Coke merchandise, including a Dennis Hopper print of the iconic Coke bottle sculpture and prototypes of cans designed for space travel. We had a branded fridge filled with Sprite, TaB, Coca-Cola Classic, and Diet Coke in the garage. Later, other drinks my dad had a hand in — such as Powerade, Surge Cola, Cherry Coke, OK Soda, and Fruitopia — took their place among the neat rows. 

He was also part of the New Coke launch, a story told so frequently that he was even referenced on The Simpsons. Despite his “failure,” he still landed a cover story for Fortune Magazine with the headline “So You Fail. So What?” The real story is that New Coke was actually a success for the company because it boosted sales and consumer interest in Coca-Cola Classic.  

Diet cola — but with a difference

Diet Coke was invented as a top secret response to the growing demand for diet sodas in the early 1980s. While Diet Rite Cola, TaB, and Diet Pepsi had already entered the market, Coca-Cola hesitated to pursue a diet drink. TaB was a diet drink that helped you “keep tabs” on your calorie intake. 

“I asked Coke’s president, Brian Dyson, ‘What about Diet Coke? We don’t have it,’” my dad recalls. “The response was, ‘Look, we’ve done a lot of trials, but Ike [Herbert — the acting marketing head at the time] doesn’t think it’s a good idea.’” McCann Erickson, Coke’s main agency of record, also heavily influenced Herbert with their own agenda. 

My dad continued pushing for Coke to take the diet plunge. The breakthrough came when the company’s CEO, Paul Austin, was replaced by Cuba native Roberto Goizueta, who sought to drive change within the company. He believed in my dad and recognized Diet Coke’s potential. So he allowed him to start with “Project Harvard,” named as such because my dad postponed post-graduate studies at Harvard Business School to head the project. 

Dad’s idea was to position Diet Coke not just as a diet soda but as a regular soft drink with no calories. This strategy ultimately led to its success. To launch the product, my dad — known around Madison Avenue as an “enfant terrible” and nicknamed the “Aya-Cola” due to his sometimes polarizing management style — went to New York to hire a new advertising agency. He wanted to disrupt the status quo for advertising agencies, which only cared about brand awareness. Coke had plenty of that. All my dad cared about was whether people would buy it. 

“The idea behind it was that we couldn’t succeed in launching it as a diet drink,” he says. “The diet market was 10% of the market. We had to launch it as a regular soft drink without calories. Not a diet drink.” 

The advertising campaign, which famously touted drinking Diet Coke, “Just for the taste of it,” shifted the focus away from the company’s traditional diet message and emphasized the product’s taste. TaB was positioned as a drink for models and “beautiful people” who wanted to be slim, and so was Diet Pepsi. Diet Coke was presented as a regular soft drink with no calories, and the bold stance declared it was good enough to be enjoyed for its taste, countering the existing cultural perception that drinking diet soft drinks meant sacrificing taste. 

New Coke fizzled, but Diet Coke bubbled up to the top

This shrewd marketing strategy proved successful. In July 1982, Coke took over Radio City Music Hall to launch the brand and even brought in the Rockettes to celebrate this new era. Diet Coke became an immediate hit in the United States. Most supermarkets, including Walmart, asked brands for a “slotting allowance,” which was used to pay for space on the shelf in case a new product didn’t sell well. Diet Coke was launched without a slotting fee because everyone wanted it. 

A few months later, my dad called a press conference and declared Diet Coke the third-largest soft drink in America, surpassing 7UP and Dr. Pepper. Both brands challenged his statement, but industry pundits agreed with my dad. By 1983, one year post-launch, it was the number-one diet drink.

Five years later, my dad left the company for the first time. People blamed New Coke’s failure, but that was in 1985, and he didn’t leave the company until 1988. “I left primarily because I didn’t feel my efforts were being appreciated,” he tells me. “And I was tired. I was being blamed for some of the bad things at Coke and not being credited for the good things, like the launch of ‘Coke Is It.’” 

After my dad left, the company retained him as a consultant, during which time he worked on critical strategic projects such as TaB Clear. Another project my dad was hired to do was investigating why Diet Coke was not working in Europe. His research found that “diet” connoted medicine and recommended changing the name from Diet to Light. The company took no action. 

In the summer of 1993, my Dad was asked back to the company to do “the marketing thing,” as the hiring executives put it. He demanded that he be named the company’s first-ever Chief Marketing Officer because he believed marketing was just as crucial to a company as finances and operations. 

“One of the first things I did was implement what I had discovered in my projects when I was a consultant to the company,” he says. “I immediately changed the name from Diet Coke to Coca-Cola Light abroad, except for the U.K. and Australia.” The brand took off, and it is still Coca-Cola Light to this day. By the end of the 1980s, Advertising Age had named Diet Coke the “Brand of the Decade.”

The Cola Wars at home

Being part of the Coke family in Atlanta was a lot of fun. My father received deliveries of every Coke product imaginable in flats that the trucks would leave between the two garage doors of our red brick house. Family vacations always included side trips to grocery stores to see how the brand was merchandised. I even met Yoko Ono and Bill Cosby. 

I was a big fan of the brand, both by circumstance and with genuine adoration as a first-generation immigrant sold on the American dream. Coke was synonymous with being American, just as much as the McDonald’s Happy Meals I begged my parents for instead of the mole my maternal grandmother made while visiting from Mexico City where my parents were born and raised. They still make fun of how I eventually became a restaurant critic, even though I only wanted pizza and cheeseburgers as a child.

I am part of the generation that remembers when we didn’t drink from or carry reusable water bottles everywhere. I remember drinking plenty of soda. A person might consume a lot due to having access to so much. Habits could form — some of them bad. As someone with an addictive personality, my relationship with Diet Coke became exclusive and a little bit toxic. I never drank water, only Diet Coke. I started each day with an icy can, and there were many nights in college when I would fall asleep with a fresh one popped open and ready on my nightstand — for midnight sips, I guess? It was a constant, like the crisp, hard pack of Marlboro Lights on my writing desk in my home office. 

The first sip after popping open a cold can of that effervescent dark nectar was like a siren song. I craved it, and no other drink could unseat its hold. That sparkling chemical elixir did something magical to my brain and gave me energy. Some days, I would drink five or more without a sip of water in sight.  

I was always fat as a teenage girl in the 1990s, when a particular diet culture was in full force. Being overweight was not cool, and society was much less body-positive than it is today. Before the internet, that messaging came at us via magazines, TV, and the girls around us. Now it can come from many places — most of them through the phone in your hand. To make things worse, I was a weird Jewish kid with parents who spoke with thick Spanish accents in the South. And I sure didn’t look like the other girls at my school in Atlanta, where Coke is headquartered. I was an art kid who wore nothing but black, with incredibly fair skin and dark frizzy curls. My mom used to say she could always spot my younger sister and me at a dance class because we were the only girls with dark hair in a sea of blondes. 

I thought being skinny and having straight, shiny hair would solve everything. The models in the dELiA*s clothing catalogs more alternative teens — like myself — shopped from featured waifish nymphs with pixie cuts. I didn’t see my body anywhere. 

Even though that fridge had every Coke drink imaginable, I never drank regular Coke because I was terrified of the added calories. “I like to eat my calories, not drink them,” I’d say while ordering a double cheeseburger, large cheese fries, and an extra-large diet soda. 

According to my dad, I am not alone in pairing Diet Coke with fatty meals. “The culture’s mindset is about minimizing the damage. It’s not about the product itself,” he says. People think, ‘If I drink Diet Coke, I can indulge in other things,’ even though it may not always be the healthiest choice. It’s all about choosing the lesser evil to indulge in things you like.”

Sweeteners start scares and sales sink

There had been concerns about Saccharin, which was used to sweeten TaB and Diet Coke, after a 1981 study that found it caused bladder cancer in rats. The panic built with nightly news feeds with words like “cancer” and “death.” Coca-Cola and other companies had to make a change. “The sweetener industry ended up in a fight, and we had to move to aspartame,” says my dad. Aspartame eventually experienced similar health scares, and diet soda became taboo with the health-conscious or, like me, health-anxious. Diet sodas started losing their market share, and by the early ’00s, they were down 30%. Diet soda was not it anymore.

As a result, Diet Coke became something I felt I needed to kick, and I know many of my friends felt the same — some still do. Former self-proclaimed “Diet Coke Addicts” in my friend group wear their years without one as a badge of honor, just like I tally my years as a former smoker (13 years and counting). 

To lose weight after I had a baby, I went on yet another diet in 2013 – maybe the 26th of my life. This time, it was one where you cut out everything artificial, added sugars, and all the fun stuff to “reset” your body. Diet Coke and my beloved bright pink Sweet’N Low packets were some of those things. After an admittedly painful withdrawal period, I forgot about soda and a lot of other bad eating habits as I lost weight. “Cleansing” my body felt like a victory because I had worried about its effects on my body after decades of questionable but fun choices. I stopped drinking Diet Coke for a few years.

Diet Coke pops back into pop culture

A decade later, Diet Coke is back on track, and soda culture is everywhere on social media, especially TikTok, where a “crispy Diet Coke” is touted as a treat. It may be due to trends and shows like The Secret Lives of Mormon Wives, which have elevated Utah soda shop culture, where combinations like Dr. Pepper, pickles, and coconut milk are considered perfectly normal. I think it’s because the taboo is gone. Also, many younger consumers don’t remember the health scare that led many to give it up in the first place. They have numerous choices regarding drinks, and there are worse options than Diet Coke. 

I asked my dad why he thinks Diet Coke is experiencing a surge in popularity with younger generations. “My assessment might surprise you,” he says. This generation is tired of innovation and has been returning to some nostalgia. People today enjoy trying new things. We’ve been educated to go for newness and creativity. When something new comes in, something old has to go out.” 

My middle-school-aged daughter prefers Diet Coke even though we have what I jokingly refer to as “full-fat Cokes” stored next to it. She says she prefers the taste of Coca-Cola Classic, not because it’s calorie-free. However, her generation has a different relationship with diet culture than those originally raised on Diet Coke, although it still exists. It’s just different now. Today’s teen girls receive plenty of negative messaging about their bodies via “skinny girl” culture on TikTok and YouTube, but they also have the body positivity movement to balance it. That’s a modern concept my generation didn’t have the privilege of experiencing.

Today, I drink Diet Coke — just not as much because I prefer the taste and find regular Coca-Cola too sweet, especially when paired with rich foods like my beloved cheeseburger and fries. I don’t think of it as a diet drink, though. It’s just a soft drink, so I suppose my dad’s brand positioning still holds. Now that I have a house and garage, my drink fridge has a spring-loaded organizer of neat rows of beverages, mainly Coke products. I’m a loyal one. But I don’t feel the same guilt that made me give it up years ago. Our current relationship status is more casual than earlier in my life because age has taught me the value of moderation in life’s little pleasures. Diet Coke included.