Diet Sodas Could Raise Diabetes Risk by 129%

If you’re trying to  lose weight, maintain a healthy weight or just avoid excess sugar, you might lean on diet sodas and other diet drinks. We totally get it—after all, drinking lots of sugar-sweetened beverages has been linked with an increased risk of heart disease, stroke, insulin resistance and a shorter life.

But now, a new study presented at NUTRITION 2025, the annual meeting of the American Society for Nutrition, suggests that diet drinks might not be the best thing to sip. Study authors also published their findings in Current Developments in Nutrition. Let’s break down what they found. 

How Was This Study Conducted?

Researchers drew data from the Coronary Artery Risk Development in Young Adults (CARDIA) study, a 30-year study that started in 1985. It included 4,654 adults, almost 55% women, with an average age of 25 when the study began—also called the baseline. 

Participants’ diets were assessed at baseline and again at years seven and 20. Specifically, researchers were looking for the cumulative average intake of artificial sweeteners, diet beverages, aspartame and sucralose. Participants were placed into categories, called quintiles, based on their intake of these substances.

Researchers were also looking for diabetes diagnoses over the 30 years of follow-up, of which there were 691 cases. They defined diabetes as a fasting glucose higher than 126 mg/dL, glucose higher than ≥ 200 mg/dL after a glucose tolerance test, A1c higher than 6.5% or the use of diabetes medications at follow-up visits. 

What Did This Study Show?

Statistical analyses were adjusted for certain demographics, including age, sex, race, education, energy intake, physical activity, smoking status, alcohol intake, diet quality and family history of diabetes. 

Researchers found:

• Participants who consumed the most diet beverages had a 129% higher risk of diabetes compared to those who drank the least diet beverages. 
• Compared to those with lower intakes, those with the highest intake of saccharin, an artificial sweetener sometimes found in diet drinks, had a 110% increased risk of diabetes.

How Does This Apply to Real Life?

We know it’s important to limit sugar, and beverages sweetened with sugar can be a major contributor of added sugar in our diets. But this study suggests that replacing regular sodas and other sweetened beverages with diet ones may not benefit you in the ways you’re hoping. It also suggests that they may even significantly raise your risk of developing diabetes—exactly the opposite of what you might think. 

The scientific community has gone back and forth on the safety of artificial sweeteners. And while the FDA lists artificial sweeteners as “generally recognized as safe,” we also know that research is mixed on sugar substitutes—particularly when it comes to your gut health.

This study didn’t include sugar alcohols, a type of artificial sweetener, but other studies have shown that they, too, may pose some risk, including for blood clots, which increase the risk of stroke and heart attack. 

This study raises a lot of questions, which is a good thing with research. We still need more information to know if it’s only the artificial sweeteners raising the risk of diabetes, or if it’s the combination of artificial sweeteners with other additives in the beverages. We also can’t know for sure if other additives in the drinks increase diabetes risk on their own, or if it’s a combination of the diet drinks and a poor diet. 

Despite all these questions, here’s what we do know. Soda is far from being a whole food, but everything can fit in a varied and balanced eating pattern. Having a soda now and then is probably fine for most people. The key is how regularly you’re taking a soda break.

If you lean on your favorite fizzy pop to get you through a mid-afternoon slump, consider replacing it with an energizing snack, like some nuts and cheese for a mix of protein and healthy fats. You could even take a quick walk or do some push-ups against your desk to get your blood pumping. Changing your physiology is one of the quickest ways to change your energy state. And making sure you’re staying well-hydrated and well-fueled may help prevent the slump to begin with. 

If you like soda for the bubbles, consider replacing it with an unsweetened sparkling water. You’ll get all of the fizz without the additives that soda contains.

The Bottom Line

This study suggests that those who drink high amounts of diet sodas and other diet beverages may significantly increase their risk of diabetes. Soda, whether sweetened with sugar or artificial sweeteners, may be a delicious option now and then, but should probably not be a regular on anyone’s menu. If you’re a regular soda imbiber, begin replacing one soda a day with natural beverages, including water, sparkling water or unsweetened tea. Milk and juice in moderation can work, too, and add essential nutrients. Over time, continue replacing your daily sodas one at a time until you get to the level you feel good with.