Judging from the empty cans on her desk, diet cola is Angelica Lewis's go-to drink.
"I would say I average either one to two cans a day," said Lewis.
She drinks it because it gives her the caffeine kick without the calories, but a new study is making her think twice about her diet soda intake.
New research suggests people who drink diet soda daily have a 61-percent increased risk of heart attack and stroke compared to those who drank no soda.
And even though drinking regular soda has been linked to weight gain and diabetes, surprisingly, researchers did not see an increased cardiovascular risk among daily sugary soda drinkers.
Cardiologists say the report doesn't seem to make much sense.
"I can't just immediately tell Americans that diet drinks are bad for them based on this study," said Dr. Daniel Eisenberg, Foothill Cardiology.
Critics of the report say it's an association study. There's no evidence of cause and effect. And it's possible that the people who were studied may have an underlying condition like diabetes, which is a risk factor for heart disease and stroke, or people who drink diet soda may eat a diet high in calories and fat.
"Watch people when they go to McDonald's or any of the fast-food places and they order a huge Diet Coke and a Big Mac and a bunch of fries," said Eisenberg.
Eisenberg says there's no evidence to suggest sugar substitutes are to blame.
"The sugar substitutes have been proven not to be of adverse health risk, and if they were we would have a whole lot of people with medical problems based on that because diet drinks are everywhere in America," said Eisenberg.
But experts say this study should make us all aware of what we're putting in our mouths.
"I think this study doesn't really give us that much information, but it does again bring to fore the thought process of what do we eat and what does that mean, and I think we should all be thinking about that," said Eisenberg.
Other heart experts who looked at this study agree with Eisenberg.
They think it's implausible that diet drinks actually cause heart disease but it does make sense that people who drink diet sodas might make other lifestyle choices that may increase their cardiovascular risks.