What Happens to Your Body If You Have Diet Soda Every Day

Key Takeaways

• If diet soda replaces regular soda, it can help reduce sugar and calories, but it provides very little nutrition.

• Artificial sweeteners may influence cravings, gut health, and long-term health markers, although the research is still inconsistent and inconclusive.

• For most people, one can a day is generally considered acceptable, but water and other minimally processed drinks remain the healthier option overall.

Diet soda is often marketed as a better-for-you alternative to regular soda, which helps explain why it remains so popular. The diet soda market is expected to be worth more than 6 billion dollars by 2030. But even though this lighter version cuts back on sugar and calories, is it actually a healthier choice than regular soda or other drinks? And what happens if you drink it every day?

To get answers, we spoke with three registered dietitians about what nutrition diet soda offers, if any, and what may happen in the body when it becomes a regular habit.

Meet Our Expert

Diet Soda Nutrition

Nutrition varies by brand, but most diet sodas share a few basic traits.

“Diet soda provides no calories or few calories depending on the variety. Many diet sodas contain sodium, which can contribute to daily sodium levels,” says registered dietitian Alyssa Smolen, MS RDN CDN. Even so, the sodium content is usually very low—often no more than 50 milligrams per 12-ounce can—so it typically becomes a concern only if several cans are consumed each day.

Many diet sodas rely on artificial sweeteners instead of added sugar, and those ingredients may be the main source of concern. “While the research is still ongoing, artificial sweeteners found in diet soda have been associated with a higher risk of dementia and potential changes in gut microbiome health, to name a few,” says Anna Smith, MS, RDN, LDN, owner of Anna Smith Nutrition and chief nutrition officer at Lose It!. Some studies have also linked them to type 2 diabetes and general cognitive decline. Artificial sweeteners may also increase preference for sweet foods overall, which can lead to later cravings for sugary snacks.

On the plus side, diet soda is largely water. “Diet soda is mostly carbonated water,” says dietitian Nina Crowley, PhD, RDN. However, many varieties also contain caffeine, which can make them less hydrating because caffeine acts as a natural diuretic. In larger amounts—especially later in the day—caffeine may contribute to anxiety, jitters, and sleep problems for some people.

What Happens When You Drink Diet Soda Every Day?

So what should you expect if diet soda is part of your daily routine?

“Some might get a boost of encouragement by switching from regular soda to diet soda. If one swaps one diet soda a day for a regular one, they can reduce their total number of weekly calories, contributing to weight loss (if that is something they are looking to achieve),” says Smolen. Still, she cautions against counting diet soda as a hydrating beverage when trying to meet daily fluid needs, especially because of its caffeine content.

Crowley agrees and adds: “[Diet soda] does not raise blood sugar and has little to no calories, so when it replaces higher-calorie drinks, it can support changes in weight and fat mass over time. But if it is simply added in without changing anything else, it is unlikely to make much of a difference.” She also notes that for people with a healthy, balanced diet, one daily diet soda is unlikely to have a major effect on health. “For someone who’s already meeting their needs, it’s more neutral—it doesn’t add nutritional value. And while there are ongoing questions about appetite, metabolism, and the microbiome, the evidence is mixed and not definitive. So instead of asking whether diet soda is ‘good’ or ‘bad,’ a more meaningful question is: what is it replacing, and how does it fit into that person’s overall health pattern?” she says.

Smith agrees with both dietitians. “Diet soda is by no means a healthy food. So it’s not something I ever encourage people to add to their diet,” she explains. “If you’re eating balanced meals, getting enough fruits and vegetables, and overall taking care of your health, having one diet soda a day is generally not something I focus on. It’s not adding any nutritional value to your diet, but it might add enjoyment, routine, or even help someone avoid a mindless 300-calorie snack. If someone is consuming a lot of artificial sweeteners, beyond diet soda, or relying on diet soda to quench their thirst, then I would suggest limiting or tapering down to a few per week, or at least no more than one per day.”

The bottom line: if you already drink diet soda every day, one can is probably fine. If you do not drink it now, there is little reason to start unless you are replacing regular soda. Either way, water, unsweetened sparkling water, herbal tea, or small amounts of 100 percent fruit juice with no added sugar are better choices to reach for first. A balanced diet built around whole foods such as fruits, vegetables, whole grains, healthy fats, and lean proteins matters, too.