Celebrities like Elton John, Victoria Beckham and former President Bill Clinton admit to being hooked on diet soda, just like millions of Americans.
But addicts beware: A new study out this week shows that as little as one can of soda per day is associated with a 48 percent increased risk of "metabolic syndrome," which plays a major role in heart disease and diabetes.
Despite the warnings, some people just can't kick their addiction.
"It's my water, it keeps me going; it's the fluid that keeps me alive," said Amanda Sanchez, a 29-year-old working mother of two and self-professed Diet Coke junkie. "I really think I am addicted. I really think it would be very hard for me to stop."
She drinks more than a case of Diet Coke per day at home and at work.
"You hear the popping the top, you know when Amanda shows up to work: You can hear it in the Coke," her co-worker Elizabeth Perkins said.
Diet Coke and other diet sodas are hugely popular in the United States, with consumers spending $21 billion a year on the low-calorie drinks.
And while the drinks may be low in calories, they have plenty of caffeine, which can be addictive.
"People do indeed become addicted to caffeine very rapidly, and they also withdraw from caffeine very rapidly," Dr. Harris Stratyner said. "It can make their sleep patterns disturbed, it can make them restless, wired, anxious."
There is no major study that says drinking diet sodas is bad for you, but some health experts say it may have health consequences down the road.
"There is some evidence that the acid load of soda, regular or diet, has an adverse affect on bone health," Dr. David Katz said. "I would be very worried that if you are drinking 12 cans a day, diet or regular. It's potentially going to do damage to your skeleton, and eventually that can be a very serious problem."
The Coca-Cola Company says it sees nothing wrong with drinking lots of Diet Coke.
"Great taste. No calories. Wholesome ingredients. How could you drink too much?" asked Diana Garza, a spokeswoman for Coca-Cola North America.