Are there any sugar substitutes that don't cause diarrhea?

November 30, 2025 •

4 min read

Many people experience digestive distress, including diarrhea, from sugar substitutes known as sugar alcohols. However, there are indeed sugar substitutes that don't cause diarrhea, and understanding the differences can prevent discomfort.

Quick Summary

Find out which sugar alternatives are safest for sensitive digestive systems. Learn about sugar alcohols, low-FODMAP options like allulose and monk fruit, and best practices to avoid discomfort.

Key Points

Identify Sugar Alcohols: Common sweeteners like sorbitol, xylitol, and maltitol are the most likely to cause diarrhea due to poor absorption and gut fermentation.
Embrace Pure Stevia and Monk Fruit: The pure extracts of these plant-based sweeteners are generally not fermented by gut bacteria and are well-tolerated.
Consider Allulose with Caution: Allulose is a 'rare sugar' that is mostly absorbed, causing fewer issues than sugar alcohols, but should be used in moderation due to dose-dependent effects.
Always Check Labels: Many 'natural' sweetener products contain blended ingredients like sugar alcohols. Ensure you are purchasing pure extracts to avoid digestive issues.
Test Individual Tolerance: Everyone's body reacts differently. Start with small portions of new sweeteners and track your symptoms to find what works best for you.
Prioritize Moderation: Regardless of the sweetener chosen, consumption should be moderate. Large doses of any poorly absorbed substance can potentially cause digestive upset.

For many people, enjoying a sugar-free treat is met with unpleasant digestive side effects, most commonly diarrhea. The reason for this lies in how different sweeteners are processed by the body. While some pass through the gut with minimal issue, others, particularly sugar alcohols, can cause significant distress due to their poor absorption and subsequent fermentation by gut bacteria.

Understanding the Cause of Diarrhea from Sweeteners

Sweeteners can be broadly categorized into caloric and non-caloric types. While non-caloric options seem like the healthier choice for managing blood sugar and weight, some can have a disruptive impact on your digestive system. The key to avoiding discomfort is understanding why certain ingredients cause problems in the first place.

The Problem with Sugar Alcohols

Sugar alcohols, or polyols, are a class of carbohydrates commonly used as low-calorie sweeteners in sugar-free gums, candies, and diet foods. Their poor absorption in the small intestine is the primary reason for digestive issues. When they reach the large intestine, gut bacteria ferment them, producing gas and causing bloating and flatulence. They also have an osmotic effect, drawing water into the colon and causing diarrhea.

Common sugar alcohols notorious for causing digestive upset include:

Maltitol: Known for causing significant digestive distress.
Sorbitol: Frequently found in sugar-free gum and cough drops.
Xylitol: Can cause moderate digestive impact, though some develop a tolerance.
Erythritol: While generally better tolerated than its cousins, high doses can still lead to stomach issues for some individuals.

Gentle Sugar Substitutes Less Likely to Cause Diarrhea

For those with sensitive digestive systems, particularly individuals with IBS, opting for sweeteners that are well-absorbed or don't ferment in the gut is crucial. The following are generally considered gentler on the stomach:

Low-FODMAP and Well-Absorbed Options

Allulose: This is a "rare sugar" that is largely absorbed in the small intestine but not metabolized, so it has minimal caloric impact. The absorbed portion is then excreted in urine, and the small amount that reaches the colon is not readily fermented, making it far less likely to cause digestive issues than sugar alcohols. For best results, stay below the recommended single serving threshold of 0.4 g/kg body weight.
Monk Fruit Extract: Derived from a small fruit, monk fruit is a natural sweetener that is hundreds of times sweeter than sugar. It is not fermented by gut bacteria and has no known digestive side effects in its pure form. Warning: Always check product labels, as many brands blend monk fruit with erythritol or other fillers that can trigger symptoms.
Pure Stevia Extract: A natural, plant-based sweetener that does not cause fermentation in the gut. As with monk fruit, always check the label for pure extract and avoid blends containing sugar alcohols or other potential irritants.

Artificial Sweeteners to Consider

Sucralose (Splenda): Most of the sucralose consumed is not absorbed by the body. The unabsorbed portion is also not fermentable by gut bacteria, so it should not cause gas or bloating. Studies with high doses in healthy subjects showed no adverse digestive symptoms, but caution is advised for individuals with IBS until more research is available.
Aspartame and Saccharin: These are generally well-tolerated by the digestive system in moderate quantities.

Comparison of Common Sugar Substitutes


Sweetener Type	How It Causes Diarrhea	Gastrointestinal Tolerance	Example	Note on Usage
Sugar Alcohols	Poorly absorbed, fermented by gut bacteria, draws water into the colon.	Poorly tolerated, especially in high doses.	Maltitol, Sorbitol, Xylitol	Limit consumption, especially those with IBS. Maltitol is the worst offender.
Allulose	Occasional dose-dependent osmotic effect.	Generally well-tolerated in moderate amounts.	Allulose	Stay under single-serving threshold of 0.4 g/kg body weight.
Pure Monk Fruit	None known in pure extract form.	Very well-tolerated; not fermented.	Monk Fruit Extract	Check labels for added sugar alcohols like erythritol.
Pure Stevia	None known in pure extract form.	Very well-tolerated; not fermented.	Stevia Leaf Extract	Ensure it's not a blend with fillers. Brands vary widely.
Sucralose	Not fermented or osmotically active.	Generally well-tolerated; passes through mostly unabsorbed.	Splenda	Long-term effects on gut microbiota still debated.

Tips for Finding Your Personal Sweet Spot

Since individual tolerance to sweeteners varies, finding what works for you is a process of trial and error. Here are some steps to minimize digestive issues:

Start Small and Go Slow: When introducing a new sweetener, begin with a very small amount and gradually increase your intake over several days to monitor your body's reaction.
Read All Labels: Do not assume a product is safe just because it says "sugar-free." Many products, including stevia and monk fruit blends, use sugar alcohols as bulking agents.
Track Your Intake: If you suspect a sweetener is causing problems, keep a food journal to track which products you're consuming and how much, alongside any symptoms.
Consider Natural Options: Whole fruits and vegetables can be a great way to add sweetness naturally while providing fiber that supports healthy digestion.
Use Pure Extracts: Stick to pure extracts or drops of stevia or monk fruit to avoid the fillers and bulking agents found in many powdered blends.

Conclusion

While many sugar substitutes can lead to digestive discomfort like diarrhea, several well-tolerated options exist. For those with sensitive stomachs, the purest forms of monk fruit and stevia, along with the rare sugar allulose, are often the safest bets. Products containing sugar alcohols like maltitol and sorbitol are the most likely culprits for digestive upset and should be consumed with caution. By understanding the causes of sweetener-induced diarrhea and carefully reading ingredient labels, you can enjoy sweetness without the unwanted side effects.

For more information on digestive health, consult resources from trusted medical institutions such as the National Institutes of Health.

Frequently Asked Questions

Many sugar substitutes, particularly sugar alcohols like sorbitol and maltitol, are not fully absorbed by the small intestine. They travel to the large intestine where they are fermented by gut bacteria and draw water into the colon, which can lead to bloating, gas, and diarrhea.

Maltitol is often cited as the worst for causing severe digestive distress, followed by sorbitol and xylitol. Erythritol is generally better tolerated but can still be an issue in large quantities.

Pure stevia extract is generally well-tolerated and should not cause diarrhea. However, many commercial stevia products are blended with sugar alcohols like erythritol, so it is essential to read the ingredient label carefully.

Allulose is less likely to cause diarrhea than sugar alcohols because the body absorbs it more efficiently before it reaches the large intestine. However, consuming more than a single dose of 0.4 g/kg body weight may lead to dose-dependent gastrointestinal issues for some.

Pure monk fruit is an extract that provides intense sweetness without digestive side effects. A monk fruit blend typically contains bulking agents, often a sugar alcohol like erythritol, which can cause diarrhea and other GI symptoms.

Some individuals may build a tolerance to sugar alcohols over time by gradually increasing their intake, but consistent consumption can still pose a risk of digestive upset. Moderation is key.

Artificial sweeteners like sucralose and aspartame are generally well-tolerated by the digestive system in most people. Unlike sugar alcohols, they are either not fermented by gut bacteria or are absorbed before reaching the large intestine.