Artificial Sweeteners: The Truth About Stevia, Splenda & More

Written By Sean Hashmi

The Truth About Alternative Sweeteners: What Science Really Says About Diabetes, Weight Loss, and Your Health

If you've switched from sugar to alternative sweeteners thinking you're making a healthier choice, you might want to reconsider. A groundbreaking 2022 study published in Cell found that some artificial sweeteners can actually change your gut bacteria in ways that may worsen—not improve—your blood sugar control. This study is just one fascinating piece of an increasingly complex puzzle.

As a board-certified nephrologist and obesity medicine specialist, I've spent years reviewing the research on alternative sweeteners and observing their effects in my patients. Today, I'm going to share the complete truth about these sugar substitutes, grounded in the latest scientific evidence.

The Sugar Problem We're Trying to Solve

Let's start with why alternative sweeteners even exist. The average American consumes about 17 teaspoons of added sugar every single day—that's nearly 60 pounds a year! This contributes significantly to rising rates of diabetes and obesity, leading millions to search for healthier alternatives. But are these substitutes genuinely better for you?

Understanding Alternative Sweeteners: Not All Are Created Equal

Alternative sweeteners are compounds designed to provide sweetness without the calories and blood sugar impact of regular sugar. However, it's crucial to understand that they fall into four main categories, and these differences are key to making informed choices:

  1. Artificial Sweeteners

    These synthetic compounds are intensely sweet:

    • Aspartame (Equal): 200 times sweeter than sugar

    • Sucralose (Splenda): 600 times sweeter than sugar

    • Saccharin (Sweet'N Low): 300 times sweeter than sugar1

    • Acesulfame potassium (Ace-K): 200 times sweeter than sugar

  2. Natural Nonnutritive Sweeteners

    Don't let the word "natural" fool you—these still undergo significant processing:

    • Stevia: Contains steviol glycosides from the stevia plant.

    • Monk fruit: Contains mogrosides. Both are intensely sweet with virtually no calories.

  3. Sugar Alcohols (Polyols)

    Despite the name, these aren't alcohols in the way you might think:

    • Examples include erythritol, xylitol, sorbitol, and maltitol.

    • They provide 0.2 to 2.6 calories per gram (compared to sugar's 4 calories).

    • They're only partially absorbed in your small intestine—which explains their lower calorie count but also why they can sometimes cause digestive issues.

  4. Novel Sweeteners

    Often called "rare sugars" because they occur naturally but in very small amounts:

    • Allulose: Provides only 0.2-0.4 calories per gram.

    • Tagatose: About 70% as sweet as sugar.

Are Alternative Sweeteners Safe?

This is where I see the most confusion and, frankly, fear-mongering online. Major health organizations like the FDA, European Food Safety Authority, and the World Health Organization have all conducted extensive safety evaluations. They've established Acceptable Daily Intake (ADI) levels—the amount you can safely consume every day for your entire life without adverse effects.

Here's what might surprise you: these ADI limits are set with a substantial 100-fold safety factor. That means the ADI is actually 100 times less than the amount that showed no adverse effects in the most sensitive test species.

So, what does this mean in practical terms? Let's look at some specifics:

  • For aspartame:

    • The ADI is 50mg per kilogram of body weight daily.

    • For a 150-pound person, that's about 3,400mg daily.

    • A typical diet soda contains around 180mg.

    • You'd need to drink about 19 cans every single day to reach the ADI.

  • For sucralose: The ADI is 5mg/kg.

  • For stevia: The ADI is 4mg/kg (as steviol equivalents).

  • For sugar alcohols like erythritol: There's no formal ADI, as it's generally recognized as safe (GRAS).

Important Safety Considerations

While these sweeteners are considered safe from a toxicology standpoint, it's important to remember that "safe" doesn't mean "metabolically inert." A 2023 review in Nutrients highlighted that different sweeteners can have distinct effects on:

  • Gut bacteria

  • Hormone levels

  • Even gene expression

It's always wise for individuals with specific health conditions, including kidney disease, to discuss their dietary choices, including sweetener use, with their healthcare provider to ensure personalized and safe advice.

Critical exception: People with phenylketonuria (PKU) must avoid aspartame completely. This rare genetic condition (affecting about 1 in 10,000 people) prevents them from metabolizing phenylalanine, one of aspartame's breakdown products.

The Complex Truth About Blood Sugar and Diabetes

A 2020 Cochrane review, which analyzed 29 randomized controlled trials, found that nonnutritive sweeteners generally don't raise blood glucose or insulin levels when consumed in typical amounts. This makes sense—they aren't providing glucose, so there's no immediate blood sugar spike.

However, long-term observational studies sometimes paint a more nuanced picture. For instance, a large 2023 study from the NutriNet-Santé cohort, following over 100,000 people, found:

  • Those consuming the highest amounts of artificial sweeteners had a 13% higher risk of developing type 2 diabetes.

  • Each additional 100mg consumed daily was associated with a 3% increased risk.

The Microbiome Connection

Remember that fascinating Cell study I mentioned at the beginning? Researchers gave healthy volunteers packets of sucralose, aspartame, saccharin, or stevia for two weeks. They discovered that:

  • Saccharin and sucralose—but notably NOT aspartame or stevia—altered the gut microbiome.

  • These microbiome changes, in turn, impaired glucose tolerance in some individuals.

  • Importantly, the response was highly individual, appearing to depend on each person's baseline gut bacteria.

The American Diabetes Association's 2025 guidelines adopt a balanced view: nonnutritive sweeteners can be useful for reducing overall sugar and calorie intake, but they don't seem to improve glycemic control on their own.

Do Alternative Sweeteners Help with Weight Loss?

A 2021 systematic review in the International Journal of Obesity found that when people replaced sugar with low-calorie sweeteners, they lost, on average, an additional 1.06 kilograms (about 2.3 pounds) compared to control groups.

The key phrase here is "when used to replace sugar." The benefit only materializes if you're actually substituting sweeteners for calories you would have otherwise consumed. Some people fall into the "health halo" trap—drinking a diet soda, then feeling justified in eating an extra cookie. That's not a winning strategy for weight loss.

The Appetite Question

Some studies have suggested that artificial sweeteners might increase appetite by uncoupling the sweet taste from caloric content. The theory is that your brain expects calories when it tastes something sweet, and when those calories don't arrive, it might trigger increased hunger. However, a 2024 meta-analysis found that acute consumption of nonnutritive sweeteners doesn't significantly increase subsequent food intake when compared to water.

Gut Health Considerations

Your gut is home to trillions of bacteria that play crucial roles in digestion, immunity, and even mental health. A 2024 review in Nutrition emphasized that artificial sweeteners aren't as metabolically inert as once thought:

  • Saccharin and sucralose can alter gut bacteria composition in some individuals:

    • This may include decreases in beneficial bacteria like Bifidobacterium.

    • It might also involve increases in bacteria associated with glucose intolerance.

  • Stevia appears to have different effects; its interaction with the gut is unique:

    • It requires bacterial metabolism to break down steviol glycosides.

    • A 2020 study even suggested stevia might have prebiotic-like effects, potentially benefiting the gut.

  • Sugar alcohols have their own distinct microbiome effects:

    • Xylitol and erythritol can act as prebiotics, feeding beneficial gut bacteria.

    • However, they can also cause significant digestive symptoms (like bloating and diarrhea) in sensitive individuals, especially those with conditions like irritable bowel syndrome (IBS). The American Gastroenterological Association identifies them as common triggers.

Choosing the Right Sweetener for Your Needs

So, with all this information, how do you choose? Here's a practical guide based on common goals:

  • If your primary goal is blood sugar control:

    • Best choices: Erythritol and allulose (known for their minimal impact on blood glucose and insulin).

    • Also good: Stevia and monk fruit.

    • Consider avoiding: Maltitol (it has a higher glycemic impact than other sugar alcohols).

  • If weight loss is your main concern:

    • Focus more on the act of replacing high-calorie sugary options rather than on which specific alternative you choose.

    • Sucralose and aspartame are well-studied in the context of weight management.

    • Remember: Sweeteners alone won't magically cause weight loss; they are tools to help reduce overall calorie intake.

  • If you have digestive sensitivities:

    • Consider avoiding: Sugar alcohols, especially sorbitol and maltitol.

    • Stick with: Aspartame, sucralose, or stevia in moderate amounts.

    • Always start with small doses to see how your body responds.

  • If you prefer "natural" options:

    • Stevia and monk fruit are your top bets.

    • Erythritol and allulose (being "rare sugars" or a sugar alcohol derived from natural sources) would follow.

    • Remember: "Natural" doesn't automatically equate to "healthier."

  • If you're concerned about the microbiome:

    • Current evidence suggests stevia might be one of the better choices regarding gut impact.

    • You might consider limiting sucralose and saccharin if changes to gut bacteria are a primary concern for you.

  • For cooking and baking:

    • Erythritol and allulose often work well because they provide bulk similar to sugar.

    • Liquid stevia or sucralose are fine for beverages but might not provide the necessary structure for baked goods.

The Bottom Line

No single alternative sweetener is perfectly "safe" or universally "dangerous"—it's all about context, dose, and individual response. If you're trying to reduce your calorie intake or manage your blood sugar, replacing sugar with alternative sweeteners can be a beneficial strategy. However, individual responses can vary quite a bit, and moderation is always key.

Ultimately, the healthiest long-term approach is to gradually reduce your overall preference for intensely sweet tastes and to focus on a diet rich in whole, unprocessed foods. Water is still the best beverage choice, and alternative sweeteners should be viewed as helpful tools on your health journey, not magic solutions.

Don't let perfect be the enemy of good. If switching from regular soda to a diet version helps you manage your weight or blood sugar, that's a positive step, even if artificial sweeteners aren't a perfect food.

REFERENCES

  1. Suez J, Cohen Y, Valdés-Mas R, et al. Personalized Microbiome-Driven Effects of Non-Nutritive Sweeteners on Human Glucose Tolerance. Cell. 2022;185(18):3307-3328.e19.

  2. Gardner C, Wylie-Rosett J, Gidding SS, et al. Nonnutritive Sweeteners: Current Use and Health Perspectives: A Scientific Statement From the American Heart Association and the American Diabetes Association. Diabetes Care. 2012;35(8):1798-808.

  3. Ruiz-Ojeda FJ, Plaza-Díaz J, Sáez-Lara MJ, Gil A. Effects of Sweeteners on the Gut Microbiota: A Review of Experimental Studies and Clinical Trials. Advances in Nutrition. 2019;10(suppl_1):S31-S48.

  4. Lohner S, Kuellenberg de Gaudry D, Toews I, Ferenci T, Meerpohl JJ. Non-Nutritive Sweeteners for Diabetes Mellitus. The Cochrane Database of Systematic Reviews. 2020;5:CD012885.

  5. Debras C, Deschasaux-Tanguy M, Chazelas E, et al. Artificial Sweeteners and Risk of Type 2 Diabetes in the Prospective NutriNet-Santé Cohort. Diabetes Care. 2023;46(9):1681-1690.

  6. American Diabetes Association. 5. Facilitating Positive Health Behaviors and Well-Being to Improve Health Outcomes: Standards of Care in Diabetes-2025. Diabetes Care. 2025;48(Supplement_1):S86-S127.

  7. Rogers PJ, Appleton KM. The Effects of Low-Calorie Sweeteners on Energy Intake and Body Weight: A Systematic Review and Meta-Analyses of Sustained Intervention Studies. International Journal of Obesity. 2021;45(3):464-478.

  8. Movahedian M, Golzan SA, Asbaghi O, Prabahar K, Hekmatdoost A. Assessing the Impact of Non-Nutritive Sweeteners on Anthropometric Indices and Leptin Levels in Adults: A GRADE-assessed Systematic Review, Meta-Analysis, and Meta-Regression of Randomized Clinical Trials. Critical Reviews in Food Science and Nutrition. 2024;64(30):11161-11178.

  9. Sylvetsky AC, Rother KI. Nonnutritive Sweeteners in Weight Management and Chronic Disease: A Review. Obesity. 2018;26(4):635-640.

  10. Higgins KA, Mattes RD. A Randomized Controlled Trial Contrasting the Effects of 4 Low-Calorie Sweeteners and Sucrose on Body Weight in Adults With Overweight or Obesity. The American Journal of Clinical Nutrition. 2019;109(5):1288-1301.

  11. Tan VWK, Wee MSM, Tomic O, Forde CG. Temporal Sweetness and Side Tastes Profiles of 16 Sweeteners Using Temporal Check-All-That-Apply (TCATA). Food Research International. 2019;121:39-47.

  12. O'Connor D, Pang M, Castelnuovo G, et al. A Rational Review on the Effects of Sweeteners and Sweetness Enhancers on Appetite, Food Reward and Metabolic/­Adiposity Outcomes in Adults. Food & Function. 2021;12(2):442-465.

  13. Gauthier E, Milagro FI, Navas-Carretero S. Effect of Low-and Non-Calorie Sweeteners on the Gut Microbiota: A Review of Clinical Trials and Cross-Sectional Studies. Nutrition. 2024;117:112237.

  14. Plaza-Diaz J, Pastor-Villaescusa B, Rueda-Robles A, Abadia-Molina F, Ruiz-Ojeda FJ. Plausible Biological Interactions of Low- And Non-Calorie Sweeteners With the Intestinal Microbiota: An Update of Recent Studies. Nutrients. 2020;12(4):E1153.

  15. Moshiree B, Drossman D, Shaukat A. AGA Clinical Practice Update on Evaluation and Management of Belching, Abdominal Bloating, and Distention: Expert Review. Gastroenterology. 2023;165(3):791-800.e3.

  16. Rock CL, Thomson C, Gansler T, et al. American Cancer Society Guideline for Diet and Physical Activity for Cancer Prevention. CA: A Cancer Journal for Clinicians. 2020;70(4):245-271.

  17. Fitch C, Keim KS. Position of the Academy of Nutrition and Dietetics: Use of Nutritive and Nonnutritive Sweeteners. Journal of the Academy of Nutrition and Dietetics. 2012;112(5):739-58.

  18. Egan JM. Physiological Integration of Taste and Metabolism. The New England Journal of Medicine. 2024;390(18):1699-1710.

  19. Teysseire F, Bordier V, Beglinger C, Wölnerhanssen BK, Meyer-Gerspach AC. Metabolic Effects of Selected Conventional and Alternative Sweeteners: A Narrative Review. Nutrients. 2024;16(5):622.

  20. Lichtenstein AH, Appel LJ, Vadiveloo M, et al. 2021 Dietary Guidance to Improve Cardiovascular Health: A Scientific Statement From the American Heart Association. Circulation. 2021;144(23):e472-e487.

Sean Hashmi https://www.seanhashmimd.com