People with diabetes can drink sugar-free sodas, sparkling water, and naturally sweetened zero-calorie sodas without a significant spike in blood sugar. The key distinction is simple: regular soda, which packs 35 to 45 grams of sugar per 12-ounce can, will raise your blood glucose rapidly, while diet sodas and unsweetened carbonated waters contain zero sugar and have no measurable effect on blood sugar levels.
That said, not all sugar-free options are equal. Some are better long-term choices than others, and a few come with caveats worth knowing about.
Sparkling Water: The Simplest Option
Plain sparkling water, seltzer, and club soda contain no sugar, no sweeteners, and no calories. They’re the cleanest swap if you’re craving something fizzy. The American Diabetes Association recommends sparkling water as a direct substitute for soda.
If plain sparkling water feels too boring, you can add a slice of lemon, lime, cucumber, or fresh mint. Many brands also sell flavored sparkling waters with no added sugar. When choosing these, check the label for one gram or less of carbohydrate per serving and no added sugars. Brands like LaCroix, Topo Chico, Perrier, and store-brand flavored seltzers typically meet this standard.
Diet Sodas With Artificial Sweeteners
Diet versions of major sodas (Diet Coke, Coke Zero, Diet Pepsi, Diet Dr Pepper, Sprite Zero, and similar products) use artificial sweeteners that do not affect blood sugar. The most common sweeteners in these drinks are aspartame, sucralose, and acesulfame potassium. Your body doesn’t metabolize them the way it processes sugar, so they pass through without triggering a glucose or insulin response.
A 2025 systematic review and meta-analysis published in Frontiers in Nutrition confirmed that artificially sweetened beverages did not influence insulin resistance compared to unsweetened beverages in randomized controlled trials. In a separate crossover trial, glucose tolerance test results showed no significant difference in blood sugar or insulin response after drinking diet soda versus plain water, and this held true for healthy individuals and people with both type 1 and type 2 diabetes.
The 2025 ADA Standards of Care do recommend choosing water over both sugary and calorie-free sweetened drinks when possible. This reflects a general “water first” philosophy rather than evidence that diet sodas are harmful. If you enjoy diet soda, drinking it in moderation is a reasonable choice, especially if it keeps you from reaching for regular soda.
How Much Is Too Much?
The World Health Organization sets the acceptable daily intake for aspartame at 40 mg per kilogram of body weight. For a 150-pound person, that works out to roughly 15 cans of diet soda per day, a threshold most people never approach. Staying well below that limit with one to two cans daily is a common, practical guideline.
Naturally Sweetened Zero-Calorie Sodas
Brands like Zevia, Olipop (some varieties), and Virgil’s Zero Sugar use plant-derived sweeteners, primarily stevia and monk fruit extract, instead of artificial sweeteners. These are worth knowing about if you prefer to avoid synthetic ingredients.
Stevia sweeteners pass through your stomach and small intestine without being absorbed, then get broken down by gut bacteria in the large intestine. In clinical trials, people with diabetes who consumed stevia showed no significant changes in blood sugar, HbA1c (a measure of long-term blood sugar control), or insulin levels.
Monk fruit extract works similarly. In a crossover study, monk fruit consumption had no impact on blood sugar, while table sugar caused a 70% spike shortly after ingestion. Monk fruit’s sweet compounds, called mogrosides, travel straight to the colon without being absorbed, which is why they contribute zero calories. Research in animals has also suggested monk fruit may improve insulin sensitivity, though human data on this is still limited.
Both stevia and monk fruit appear to be neutral for gut health. A 2024 study found that 12 weeks of regular stevia consumption did not significantly change gut microbiota composition in healthy adults. Monk fruit may actually support beneficial gut bacteria, with in vitro studies showing it promotes the growth of helpful species like Bifidobacterium and Lactobacillus.
One Concern With Dark Diet Sodas
If you have diabetes and any degree of kidney disease, it’s worth paying attention to which diet sodas you drink. Cola-style diet sodas like Diet Coke and Diet Pepsi contain added phosphorus. High phosphorus intake can be a problem for people with chronic kidney disease, since damaged kidneys struggle to filter excess phosphorus from the blood. Elevated blood phosphorus over time can harm bones, kidneys, and heart health.
Diabetes is the leading cause of chronic kidney disease, so this overlap matters for many people. Clear diet sodas (like diet lemon-lime or ginger ale varieties) and sparkling waters generally don’t contain added phosphorus, making them a safer default if kidney function is a concern for you.
How to Read a Soda Label
Not every drink marketed as “reduced sugar” or “lightly sweetened” is truly sugar-free. Some contain real sugar blended with zero-calorie sweeteners, which will still raise blood glucose. Here’s what to look for on the ingredients list:
- Names for added sugar: cane sugar, high-fructose corn syrup, rice syrup, agave, honey, molasses, and caramel all indicate real sugar in the product.
- Ingredients ending in “-ose”: glucose, fructose, sucrose, maltose, dextrose, and lactose are all forms of sugar.
- Misleading terms: “juice,” “glazed,” “candied,” and “frosted” on a label indicate added sugar during processing.
The most reliable check is the “Total Sugars” line on the nutrition facts panel. For a truly blood-sugar-neutral soda, this should read 0 grams. Also check total carbohydrates, since anything above 1 gram per serving is worth questioning.
Ranking Your Options
If you’re trying to decide what to stock in your fridge, here’s a practical hierarchy from best to “fine in moderation”:
- Plain or fruit-infused sparkling water: Zero sugar, zero sweeteners, zero concerns. The most universally recommended option.
- Flavored sparkling water (no added sugar): Check for under 1 gram of carbs per serving. Essentially the same as plain sparkling water with natural flavoring.
- Stevia or monk fruit sweetened sodas: Zero blood sugar impact, plant-derived sweeteners, and some potential gut health benefits. A good choice if you miss the taste of real soda.
- Traditional diet sodas: No effect on blood sugar, widely available, and affordable. Best consumed in moderation, and consider choosing clear varieties over colas if kidney health is a factor.
Regular soda, fruit-juice-based sodas, and “lightly sweetened” sparkling drinks with real sugar remain the only carbonated options that people with diabetes genuinely need to avoid or carefully portion-control. Everything on the list above gives you the fizz without the glucose spike.