Diet soda may not be as healthy as you think. Research shows excessive diet soda drinking can increase sweetness cravings, erode tooth enamel, and alter your gut microbiome.
While scientific evidence links diet soda to an increased risk of Alzheimer’s, dementia, and ischemic stroke, experts agree more research is needed.
This article was medically reviewed by Samantha Cassetty, MS, RD, nutrition and wellness expert with a private practice based in New York City.
Just because diet soda doesn’t contain sugar or calories, it doesn’t mean it’s healthy for you.
Whether it’s Diet Coke, Coke Zero, or the countless number of “light” sodas offered on grocery store shelves, it’s important to realize that instead of sugar, beverage companies typically use artificial sweeteners like aspartame, saccharin, and sucralose to mimic the taste of non-diet sodas.
The fact that diet sodas rely on sugar alternatives to satisfy your cravings of something sweet and bubbly should be the first warning sign: Diet soda is not necessarily a health-conscious choice, nor does it offer nutritional value.
So while choosing diet soda over regular soda may seem like a healthy decision, there’s more to the drink than meets the taste bud. Here’s what you need to know.
5 reasons diet soda may be bad for you
If you drink a reasonable amount of diet soda — or as the Mayo Clinic puts it, “a can or two a day” — it’s unlikely you’ll experience major negative health effects. But over time, the paradox of thinking that diet soda is healthier than regular soda can take a toll on your health in several ways.
Diet soda may increase sugar cravings: Since diet soda is artificially sweetened, it can change how you associate sweetness with caloric intake. Diet soda has been shown to increase cravings for sweets, according to various studies, including one published in 2019 in Pediatric Obesity. In turn, the increase in cravings may actually lead to consuming more calories.
Diet soda may not be effective for weight loss or diabetes: While it can seem like cutting back on sugar by replacing it with artificial sweeteners will be beneficial for weight loss or diabetes, evidence suggests otherwise. “Diet soda does not promote weight loss and it has no effect on glycemic response in adults with diabetes. Therefore, diet soda should not be used as a weight-loss strategy or means to control diabetes,” says Rebecca Oh, RD, clinical dietitian at USC Verdugo Hills Hospital.
Diet soda may alter your digestive tract: “Diet soda can alter your gut microbiota, which can have negative impacts on digestion and hormone regulation,” says Oh. More research is needed to understand exactly which artificial sweeteners affect gut bacteria and how. So far, preliminary studies have found that saccharin, sucralose, and stevia may alter the bacteria in your gut, though it’s unclear what impact this may have on your health.
Diet soda may cause kidney damage: “Long-term consumption of diet soda can increase production of free radicals in renal tissues, potentially causing damage to the kidneys,” says Oh. Additionally, a 2017 study published in the Clinical Journal of the American Society of Nephrology showed that diet soda consumption is linked to a higher risk of kidney disease.
Diet soda may lead to tooth decay: Think diet soda is better for your teeth because it doesn’t contain sugar? Think again. Even though it’s sugar-free, diet soda is acidic thanks to ingredients like citric acid, phosphoric acid, citric acid, and tartaric acid. These ingredients can contribute to tooth enamel erosion, at almost the same rate as non-diet soda, according to Colgate.
What scientific research says
Over the years, numerous studies have reported links between diet soda with weight gain and serious, life-threatening diseases.
Scientific opinion is mixed and, at times, conflicting. While studies focus on the dangers of artificial sweeteners, what’s important to understand is they aim to find correlations, not necessarily cause-and-effect:
A 2017 study published in Stroke found that, among over 3,000 participants, an increase in artificially sweetened soda consumption was associated with an increased risk of Alzheimer’s disease, dementia, and ischemic stroke.
Another study in Stroke, published in 2019 found that, among 81,7214 women, women who drank more than two artificially sweetened drinks per day were at greater risk of ischemic stroke, coronary heart disease, and premature death.
Recently, a 2019 study published in JAMA Internal Medicine, found that those who drink two diet sodas a day are more likely to die from circulatory diseases, as well as increased mortality overall, compared to those who had one diet soda or less a month.
Some studies have shown a link between artificially sweetened beverages and weight loss, but in a 2017 review published in PLoS Medicine researchers concluded that there are too many studies of this nature with questionable funding and sponsorship from large industries. Therefore, more unbiased research is needed to untangle the truth.
A 2016 study published in Applied Physiology, Nutrition, and Metabolism found that the artificial sweetener aspartame was associated with insulin intolerance — which increases risk of prediabetes and type 2 diabetes — among obese individuals, but not lean ones. The researchers suggest that this might be related to another 2014 study’s findings that aspartame was linked to changes in gut bacteria that may affect insulin control.
Diet soda alternatives
For most people, cutting diet soda out completely may not be the answer. But of course, moderation is key. “If you are going to drink a soda, drink a very small serving, 6 to 8 ounces max, and work on weaning your cravings,” says Oh. She says this goes for diet soda or regular soda.
She also says that drinking soda, diet or regular, will not hydrate you as well as drinking good old-fashioned water — add a spritz of lemon or lime juice for flavor.
“Rather than focus on the ‘limit’ of how much diet soda you can drink, I encourage you to focus on how best to promote your health. Water is the best way to hydrate your body, quench your thirst, and promote health,” says Oh.
If you’re missing something fizzy, Oh recommends unsweetened sparkling water or unsweetened tea over other beverage options.
While more research is needed, it is clear that drinking diet soda should be met with a mindful examination of your eating and diet habits.
Since diet soda offers zero nutritional value, and could lead to overeating if unchecked, it’s best to explore other alternatives that could have a better impact on your weight and overall health.