Last updated: November 2025
Short answer: Yes—most diet and “zero sugar” sodas contain 0g carbs and won’t directly knock you out of ketosis. However, keep checking your labels, prioritize water/electrolytes, and use diet soda in moderation.
Keto Basics: Carbs, Ketosis, and Beverages
Ketosis is a metabolic state triggered by consuming very few carbohydrates while increasing fat intake and maintaining moderate protein. Since most diet sodas list 0 calories and 0g carbs, they may fit within your diet. What matters more is the rest of your day: protein, fiber-rich veggies, and total calories. If having a zero-carb soda helps you stay consistent and satisfied, it can be a reasonable option in moderation.
Sweeteners 101: Which Are Keto-Friendly?
Most diet sodas use non-nutritive sweeteners that don’t contribute measurable carbs:
- Aspartame (Diet Coke, Diet Pepsi)
- Sucralose (some “Zero” or diet variants)
- Acesulfame K (often blended with others)
- Stevia and/or monk fruit (select brands)
Sugar alcohols: You may find these in “keto” snacks, protein bars, or sugar-free candies rather than in sodas. Erythritol provides nearly 0 net carbs because it isn’t metabolized into glucose, while maltitol is partially absorbed and can contribute some digestible carbs and calories. ¹ ²
Can You Drink Diet Soda on Keto? “Diet” vs. “Zero Sugar” vs. “Keto” Sodas
- Diet and Zero Sugar are largely branding differences. Both usually mean 0g sugar and 0g carbs per serving—but always check the label to be sure.
- Energy drinks: Carb content varies widely—some are sugar-free, others pack significant carbs. Check the label.
- Flavored waters: Most are unsweetened or use non-nutritive sweeteners, so they’re usually carb-free — but some varieties add sugar. Choose carb-free options if added sugar does not fit in your diet.
- “Keto” sodas: Typically contain artificial sweeteners and have little to no carbohydrates; check total carbs and serving size to be sure.
- Tonic vs. club soda: Regular tonic has sugar; diet tonic is usually 0g. Club soda/seltzer/sparkling water are naturally 0g.
Best Picks & What to Limit
Keto-friendly choices
- Classic diet sodas (0g carbs) or “Zero Sugar” colas
- Unsweetened seltzer/club soda/sparkling mineral water
- Stevia/monk-fruit sodas with 0g carbs
- Unsweetened iced tea, black coffee, or coffee with a measured splash of low-carb milk/cream
- Electrolyte water or 0g mixes (handy on keto)
Limit or skip
- Regular sodas and sweetened teas (high sugar)
- “Light” or “reduced sugar” sodas with 4–12g carbs per can
- Multiple cans per day if you notice cravings, bloating, or sleep/caffeine issues
Make it effortless: Keep your meals protein-forward and low in net carbs so a diet soda doesn’t derail the day. Our Weight-Loss Meal Plan and Build-a-Meal Plan make it easy; quick breakfasts like Overnight Oats help you stay consistent.
Common Pitfalls (Cravings, Fasting, Dental, Caffeine)
- Cravings & appetite: Some people may find sweet-tasting drinks increase their snack urges.³
- Hydration & electrolytes: : Keto can have a diuretic effect early on—diet soda doesn’t replace lost sodium, potassium, or magnesium. Electrolyte replacement is important.
- Dental health: Carbonation and acidity can wear enamel over time. Use a straw and rinse with water after consumption. ⁴
- Caffeine: Late-day caffeine may disrupt sleep, which can nudge appetite up the next day. Switch to caffeine-free in the afternoon. ⁵
FAQs
Will diet soda kick me out of ketosis?
Not by carbs—most list 0g. If it leads to more snacking or higher calories, that can slow progress. Track how your body responds.
Is Coke Zero (or Diet Pepsi/Diet Coke) keto?
Yes—these are typically 0g carbs per serving. Scan your can to confirm.
What about natural options like stevia or monk fruit?
Stevia/monk-fruit sodas are usually fine on keto. Taste and GI tolerance vary—pick what suits you.
Are sugar alcohols okay?
Most diet sodas may not use them. For “keto snacks,” erythritol is usually very low net-carb; maltitol can behave more like sugar—check labels.
How much diet soda is too much?
There’s no strict limit, but it’s best to minimize soda intake and prioritize water—including carbonated or unsweetened flavored varieties. If you’re drinking multiple cans a day or replacing water and electrolyte-rich fluids with soda, it might be a good idea to cut back.⁶
Next Steps
Use diet soda as an occasional tool—not a hydration plan. Build the day around protein, veggies, and smart carbs. If you want done-for-you low-carb structure, explore our Weight-Loss Meal Plan or customize with Build-a-Meal Plan.
Disclaimer: This article is for general information and isn’t medical advice. Consult your clinician if you have specific conditions.
References
1. Solan M. How healthy is sugar alcohol? Harvard Health. December 18, 2023. Accessed November 2, 2025. https://www.health.harvard.edu/blog/how-healthy-is-sugar-alcohol-202312183002
2. Mazi TA, Stanhope KL. Erythritol: An In-Depth Discussion of Its Potential to Be a Beneficial Dietary Component. Nutrients. 2023;15(1):204. doi:10.3390/nu15010204
3. Why artificial sweeteners can increase appetite - The University of Sydney. Accessed November 2, 2025. https://www.sydney.edu.au/news-opinion/news/2016/07/13/why-artificial-sweeteners-can-increase-appetite.html?utm_source=chatgpt.com
4. Dental Erosion | American Dental Association. Accessed November 2, 2025. https://www.ada.org/resources/ada-library/oral-health-topics/dental-erosion
5. The connection between sleep and hunger. Cleveland Clinic. March 21, 2025. Accessed November 2, 2025. https://newsroom.clevelandclinic.org/2025/03/21/the-connection-between-sleep-and-hunger
6. Limit low-calorie sodas and drinks, and stick to water instead, researchers advise. American Heart Association. July 29, 2018. Accessed November 2, 2025. https://www.heart.org/en/news/2018/07/29/limit-low-calorie-sodas-and-drinks-and-stick-to-water-instead-researchers-advise
