Diet Coke contains artificial sweeteners and caffeine, which can stimulate the digestive system, leading to increased bowel movements for some individuals.
If you’ve ever noticed an urgent bathroom trip after drinking Diet Coke, you’re not alone. Many people experience digestive changes from this popular zero-calorie beverage. The culprit lies in its artificial sweeteners and other ingredients that can stimulate bowel movements.
How Diet Coke Affects Digestion
Diet Coke contains several ingredients that may speed up digestion:
Artificial Sweeteners as Laxatives
The primary sweeteners in Diet Coke – aspartame and acesulfame potassium – can have laxative effects. While not as potent as sugar alcohols like sorbitol (found in sugar-free gum), these sweeteners may:
- Draw water into the intestines
- Stimulate gut motility
- Alter gut bacteria balance
Caffeine’s Stimulating Effect
Diet Coke contains about 46mg of caffeine per 12oz can. Caffeine acts as a stimulant that:
- Increases colon contractions
- Speeds up gastric emptying
- May trigger the gastrocolic reflex
Scientific Studies on Diet Soda and Digestion
| Study | Findings |
|---|---|
| ZOE Research (2025) | Artificial sweeteners altered gut microbiome in 68% of participants |
| American Journal of Clinical Nutrition | Diet soda drinkers had faster transit time than water drinkers |
Comparing Diet Coke to Other Digestive Triggers
While Diet Coke may cause bowel movements, other foods have stronger effects:
Coffee vs. Diet Coke
Regular coffee contains more caffeine (95mg per cup) and additional digestive stimulants like chlorogenic acids. As noted in our article on the best coffee makers, brewing method affects caffeine content.
Dairy vs. Artificial Sweeteners
Lactose intolerance affects about 65% of adults globally, while artificial sweetener sensitivity is less common but still significant.
When to Be Concerned
Occasional digestive changes from Diet Coke are normal. Consult a doctor if you experience:
- Chronic diarrhea after consumption
- Blood in stool
- Severe abdominal pain
Alternatives to Diet Coke
For those sensitive to artificial sweeteners but wanting flavor, consider:
- Sparkling water with lemon
- Herbal iced tea
- Homemade fruit-infused water
If you enjoy carbonated drinks, our guide to the best blenders for mixed drinks can help create healthier homemade alternatives.
The Bottom Line
Diet Coke’s combination of artificial sweeteners, caffeine, and carbonation can stimulate digestion in sensitive individuals. While generally safe in moderation, those with frequent digestive issues may want to limit intake or explore alternatives.
