Diet Soda and Diabetes: Carbs, Glycemic Index and Portions
A can of diet soda has about 0.4 g of carbohydrate (0.4 g net). Glycemic index: not applicable. Yes, in moderation. Diet soda has no carbohydrate, so it does not raise glucose directly.
Diet soda is sweetened with high-intensity sweeteners that contribute no carbohydrate. The FDA has reviewed these sweeteners and considers those it has approved safe for the general population under their conditions of use.
Plain water, sparkling water and unsweetened tea are still the simplest everyday drinks. Regular soda, on the other hand, is a large amount of sugar in liquid form, which is why many people switch.
Carbs in diet soda by portion
| Portion | Grams | Carbs (g) | Fiber (g) | Net carbs (g) | Protein (g) |
|---|---|---|---|---|---|
| can | 355 | 0.4 | 0 | 0.4 | 0 |
| bottle | 474 | 0.5 | 0 | 0.5 | 0 |
| 100 g (for comparing foods) | 100 | 0.1 | 0 | 0.1 | 0 |
Source: USDA FoodData Central, FDC ID 171876 (Diet soda). Net carbs here means carbohydrate minus fiber. “Net carbs” is not an FDA-defined term, so total carbs are shown too. Values are estimates for a typical item; brands, ripeness and size vary.
Glycemic index and glycemic load
Glycemic index: not applicable. Almost no carbohydrate, so a glycemic index does not apply.
Glycemic index is only one piece of the picture. The same food can give a different response depending on ripeness, cooking, what you eat it with and your own body, so your meter or CGM is the best guide.
How diet soda fit the plate method
Diet Soda are a drink, not a plate section, so the plate method does not place them. What matters is what is in the cup or glass. The CDC describes the plate method as half non-starchy vegetables, a quarter protein and a quarter carbohydrate foods. See the diabetic meal plan guide for how it works, or drop diet soda onto a meal in the meal planner to watch the plate fill.
Portion ideas and pairings
- One can with a meal rather than all day.
- Alternate with water.
- Check labels on flavored waters and teas, which can contain sugar.
Pairs well with: water, unsweetened tea, a balanced meal.
Related foods
Beer, regular
can: 12 g carbs
Red wine
serving: 3.8 g carbs
Coffee, black
cup: 0 g carbs
Banana
1 medium: 27 g carbs
See all foods and the low glycemic foods list
Frequently asked questions
Is diet soda safe for diabetes?
It has no carbohydrate. See our sweeteners page for what each sweetener is and what the FDA says.
How many carbs are in a can of diet soda?
About 0.4 g of carbohydrate, of which about 0 g is fiber, so roughly 0.4 g net carbs. Values are from USDA FoodData Central for 355 g and are estimates; brands and sizes vary.
Information only, not medical advice. Your care team may set different targets for you, and only a lab test ordered by a clinician can diagnose diabetes or prediabetes. See our medical disclaimer.
Sources
- USDA FoodData Central: Diet soda (FDC ID 171876)
- Atkinson FS et al. International tables of glycemic index and glycemic load values 2021. Am J Clin Nutr 2021;114(5):1625-1632
- CDC: Diabetes Meal Planning (plate method and carbohydrate counting)
- ADA Standards of Care in Diabetes—2026, Section 5: Facilitating Positive Health Behaviors
- FDA: High-intensity sweeteners
Last reviewed: by the Diabetes Blogs editorial team. Information only, not medical advice.
