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If you've ever grabbed a diet soda, stirred a sugar-free sweetener into your coffee, or eaten foods labeled "sugar-free," you've likely consumed artificial sweeteners. These sugar substitutes have become incredibly common in our modern diet—showing up in everything from beverages and desserts to yogurt and even chewing gum. They promise the sweetness we crave without the calories or blood sugar spikes that come with regular sugar.
But are they actually good for us?
This is a question scientists, doctors, and health organizations have been debating for years. Some research suggests artificial sweeteners can help with weight loss and diabetes management, while other studies link them to potential health risks like heart disease and stroke. The conflicting information can feel overwhelming, especially if you're just starting to pay attention to what you eat and drink.
In this article, we'll break down a comprehensive 2025 research review by Ray and Palui that examined the benefits, risks, and ongoing controversy surrounding artificial sweeteners. The authors—both endocrinology experts (doctors who specialize in hormones and metabolism)—reviewed dozens of studies to provide a balanced look at what we currently know about these widely used sugar substitutes.
What makes this review important: With nearly 30% of pregnant women and countless adults and children consuming artificial sweeteners daily, understanding their real effects on our health matters more than ever (Ray & Palui, 2025). This review doesn't just look at one or two studies—it synthesizes findings from multiple research approaches, including randomized controlled trials (the gold standard of scientific research) and long-term observational studies that follow people over many years.
Areas of ambiguity you should know about: As you'll see throughout this summary, the research on artificial sweeteners is genuinely mixed. Short-term studies often show different results than long-term studies. Research on animals sometimes contradicts findings in humans. And different types of artificial sweeteners may have different effects on the body. The authors are transparent about these inconsistencies, and we'll address them as they come up.
Let's dive into what science actually tells us about artificial sweeteners—the good, the uncertain, and the potentially concerning.
Artificial sweeteners, also called non-nutritive sweeteners (NNS), are compounds designed to taste sweet without providing significant calories or affecting your metabolism the way regular sugar does (Ray & Palui, 2025). They're popular because they can be hundreds—or even thousands—of times sweeter than table sugar, which means you need only tiny amounts to get that sweet taste.
There are two broad categories of sugar substitutes (Ray & Palui, 2025):
Synthetic (man-made) artificial sweeteners:
Natural sweeteners:
Each of these sweeteners has something called an "Acceptable Daily Intake" or ADI—basically, the amount that regulatory agencies like the FDA (Food and Drug Administration) consider safe to consume every day for your entire life (Ray & Palui, 2025). For example, the FDA's ADI for aspartame is 50 mg per kilogram of body weight, while for sucralose it's 5 mg per kilogram.
Important context: The ADI levels are set with large safety margins. For a 150-pound (68 kg) person, reaching the ADI for aspartame would require drinking about 19 cans of diet soda in a single day—far more than most people consume (Ray & Palui, 2025). This matters because many of the scary findings in animal studies used doses 20-40 times higher than the ADI.
According to Ray and Palui (2025), artificial sweeteners do offer several legitimate benefits, particularly for certain groups of people. Let's break down what the research actually supports.
One of the main reasons people reach for artificial sweeteners is to cut calories and lose weight. The evidence here is mixed but shows some promise in specific situations.
What works: In randomized controlled trials (RCTs)—studies where researchers assign people to use either artificial sweeteners or regular sugar—participants who used artificial sweeteners had meaningfully lower body weight compared to those consuming sugar (Ray & Palui, 2025). One meta-analysis (a study that combines results from multiple studies) including 20 research trials found that artificial sweeteners reduced body weight when compared to sugar users, but interestingly, not when compared to people who drank plain water or took a placebo (Ray & Palui, 2025).
Who benefits most: The weight-loss effects were strongest in people with higher body mass index (BMI—a measure of body fat based on height and weight) and in those who weren't already following a calorie-restricted diet (Ray & Palui, 2025). This makes sense: if you're drinking several regular sodas a day and switch to diet versions without changing anything else, you're cutting out hundreds of calories. But if you're already carefully monitoring your calorie intake, the switch may not make as big a difference.
The stevia advantage: In one randomized trial, people using stevia maintained a stable body weight over time, while those in the placebo group actually gained weight (Ray & Palui, 2025). Among the various sweeteners, stevia and sucralose appear to have "relatively least concerning data" for weight management (Ray & Palui, 2025).
The Ambiguity Surrounding It: Here's where things get confusing. While short-term studies show weight loss benefits, long-term observational studies (which follow people over years) have found the opposite pattern. Some research has actually linked artificial sweetener consumption with increased weight gain and abdominal obesity over time (Ray & Palui, 2025). Scientists aren't entirely sure why this happens, but one theory is that artificial sweeteners might disrupt the body's natural ability to regulate calorie intake, possibly leading people to overeat other foods.
For people with diabetes or those trying to prevent it, artificial sweeteners offer a way to enjoy sweet tastes without the blood sugar spike that comes from regular sugar.
The good news: Most short- and long-term studies have found that artificial sweeteners don't directly raise blood sugar or insulin levels in healthy people, those who are overweight, or people with diabetes (Ray & Palui, 2025). This is because, unlike regular sugar, artificial sweeteners aren't broken down and absorbed by your digestive system in the same way. They don't trigger the release of incretin hormones (gut hormones that help regulate blood sugar after you eat) the way actual nutrients do (Ray & Palui, 2025).
The uncertainty: However, the picture becomes less clear when we look at long-term effects on diabetes risk. Some research suggests that chronic use of artificial sweeteners might actually be linked to developing insulin resistance (when your body's cells don't respond well to insulin) and type 2 diabetes in people who didn't have diabetes before, or worsening blood sugar control in people who already have diabetes (Ray & Palui, 2025).
Proposed mechanisms: Scientists have suggested several ways this could happen: artificial sweeteners might alter the bacteria living in your gut (your gut microbiome), change how your gut produces hormones, or interfere with the brain circuits that normally help you feel satisfied after eating sweet foods (Ray & Palui, 2025). However—and this is important—interventional studies (where researchers actually give people artificial sweeteners and measure what happens) have mostly failed to prove these mechanisms actually cause significant problems in real-world human use.
The bottom line on blood sugar: The evidence is "heterogeneous and conflicting," meaning different studies show different results (Ray & Palui, 2025). In the short term and at reasonable intake levels, artificial sweeteners appear safe for blood sugar management, but questions remain about long-term effects.
Beyond weight and blood sugar, Ray and Palui (2025) note two other well-supported benefits:
While artificial sweeteners offer some benefits, the 2025 review also uncovered concerning associations with several health problems. It's crucial to understand that many of these findings come from observational studies—research that shows connections but can't definitively prove cause and effect.
This is perhaps the most concerning area of research on artificial sweeteners, and the findings have been remarkably consistent across multiple large studies.
The landmark findings: In the Women's Health Initiative study—a major research project involving thousands of women—higher intake of artificially sweetened beverages was associated with a 16% increased risk of death from any cause and a 29% increased risk of coronary heart disease (Ray & Palui, 2025). Even more striking, women who consumed more artificially sweetened drinks had a 23% higher risk of stroke overall, with the risk of ischemic stroke (the type caused by blood clots blocking arteries in the brain) jumping by 31% (Ray & Palui, 2025).
Confirming evidence: These findings weren't isolated. Another large study called the NutriNet-Santé cohort, which followed over 103,000 participants, found that artificial sweetener use increased the overall risk for cardiovascular diseases by 9% and the risk for cerebrovascular events (problems affecting blood flow to the brain, like strokes) by 18% (Ray & Palui, 2025).
Which sweeteners are riskiest? When researchers looked at individual sweeteners, they found (Ray & Palui, 2025):
Additional heart-related concerns: A meta-analysis found that each additional daily serving of artificially sweetened beverages was associated with an 8% increased risk of cardiovascular disease and a 7% increased risk of death from any cause (Ray & Palui, 2025). Artificial sweeteners have also been linked to atherogenic dyslipidemia—abnormal cholesterol and fat levels in the blood that promote the formation of artery-clogging plaques (Ray & Palui, 2025).
Important context about these risks: It's crucial to understand that these are associations, not proven causes. People who drink lots of diet beverages may differ from non-users in many ways—perhaps they have other unhealthy habits, or they switched to diet drinks because they already had health problems. While the consistency across multiple studies is concerning, we can't say with certainty that artificial sweeteners directly cause these problems.
The possible cancer risk from artificial sweeteners has probably generated more headlines and fear than any other concern. The good news? The actual evidence is far less alarming than many people think.
The history: Early animal studies from decades ago found that very high doses of saccharin and cyclamate were linked to bladder cancer in rats (Ray & Palui, 2025). More recently, one prospective study reported higher overall cancer rates with aspartame and acesulfame-K use (Ray & Palui, 2025).
What the comprehensive evidence shows: When researchers looked at the totality of evidence, the picture became much less concerning. A meta-analysis found possible slight increases in bladder and larynx cancer risk from some case-control studies, but when looking only at the higher-quality prospective cohort studies, there was no evidence of increased cancer risk (Ray & Palui, 2025). Another systematic review examining 68 studies on five different artificial sweeteners found no significant association with cancer (Ray & Palui, 2025).
The aspartame controversy: In 2023, the International Agency for Research on Cancer (IARC) classified aspartame as a "possible human carcinogen (Group 2B)," which sounds scary but actually puts it in the same category as pickled vegetables (Ray & Palui, 2025). Importantly, the Joint FAO/WHO Expert Committee reviewed the same evidence and confirmed that aspartame consumed within the ADI limits is not associated with significant cancer risk (Ray & Palui, 2025). The FDA also stated they found no safety concerns with aspartame when used as approved (Ray & Palui, 2025).
The dose makes the poison: Here's the critical point—the cancer risks seen in animal studies appeared only at exposures 20-40 times higher than the ADI, doses far beyond what humans typically consume (Ray & Palui, 2025).
Bottom line on cancer: While we can't say with absolute certainty that artificial sweeteners have zero cancer risk at typical human consumption levels, the current evidence doesn't support significant concern when these products are used as intended.
Your gut is home to trillions of microorganisms—collectively called your gut microbiota or microbiome—that play important roles in digestion, metabolism, and even immune function. Emerging research suggests artificial sweeteners may affect these tiny residents.
What happens: Artificial sweeteners are processed by gut bacteria and may cause changes in which types of bacteria live in your intestines (Ray & Palui, 2025). These changes could potentially affect how your body regulates metabolism and inflammation (your body's defense response that, when chronic, can contribute to disease).
Digestive symptoms: Artificial sweeteners can commonly cause flatulence (gas) because they aren't completely absorbed from the gastrointestinal tract (Ray & Palui, 2025). They may also affect gut permeability (how easily substances can pass through your intestinal walls), gut motility (how fast food moves through your system), and the overall composition of your microbiome (Ray & Palui, 2025).
The research gap: While these effects have been documented, scientists are still figuring out what they mean for long-term health. The gut microbiome is incredibly complex, and we're only beginning to understand how changes in bacterial populations translate into real-world health outcomes.
Some research has raised red flags about artificial sweeteners and liver health.
Animal evidence: In studies on animals, both aspartame and saccharin have been associated with liver injury (Ray & Palui, 2025). There's also emerging evidence connecting artificial sweeteners to MASLD (Metabolic Dysfunction-Associated Steatotic Liver Disease)—the new term for what used to be called "fatty liver disease" (Ray & Palui, 2025).
What we need: The authors note that longer prospective studies in humans are necessary to truly understand the relationship between artificial sweeteners and liver disease (Ray & Palui, 2025). Animal studies don't always predict what happens in humans, so we should be cautious about drawing firm conclusions.
Ray and Palui (2025) mention several additional concerns:
Artificial sweeteners don't affect everyone the same way. Certain groups—pregnant women, nursing mothers, and children—may face unique risks that deserve special attention.
About 30% of pregnant women now intentionally consume artificial sweeteners during pregnancy (Ray & Palui, 2025). This is concerning because these compounds don't just stay in the mother's bloodstream—they've been found in amniotic fluid (the fluid surrounding the developing baby) and breast milk, meaning they can transfer to the fetus and breastfed infants (Ray & Palui, 2025).
Preterm birth risk: A meta-analysis combining data from three prospective studies found that artificial sweetener use during pregnancy was associated with a 25% higher risk of preterm birth (having a baby before 37 weeks of pregnancy), though this risk was mainly limited to late preterm delivery (34-37 weeks) (Ray & Palui, 2025). The good news is that researchers didn't find significant risks of low birth weight or having large babies (Ray & Palui, 2025).
Long-term effects on children: Prenatal exposure to artificial sweeteners has been linked to increased BMI in infants (Ray & Palui, 2025), suggesting that what a mother consumes during pregnancy might affect her child's weight and metabolism later in life.
The guidance gap: Unfortunately, there's a serious shortage of clear guidelines about the safety of artificial sweeteners for pregnant and breastfeeding women (Ray & Palui, 2025). Until more long-term research is available, the authors recommend that this sensitive population practice moderation when it comes to artificial sweetener consumption (Ray & Palui, 2025).
The safety of artificial sweeteners in kids is especially controversial because children may face higher exposure than adults in two important ways (Ray & Palui, 2025):
Current guidelines (limited as they are):
What about weight effects? The research on whether artificial sweeteners help or harm children's weight is genuinely mixed. Some studies show no effect or even weight gain in children and adolescents using artificial sweeteners (Ray & Palui, 2025). One study did find that replacing sugar drinks with artificially sweetened beverages or water was particularly beneficial for teenagers with the highest BMIs (Ray & Palui, 2025).
The bottom line for parents: Given the uncertainties and the fact that children's bodies are still developing, caution is warranted. Artificial sweeteners shouldn't be seen as a magic solution for childhood obesity, and parents should think carefully about introducing them into their children's regular diet.
If your head is spinning from all the mixed messages, you're not alone. Even the experts acknowledge that the research on artificial sweeteners is frustratingly inconsistent. Let's try to understand why.
Short-term vs. long-term studies: Ray and Palui (2025) point out a critical pattern: randomized controlled trials (which typically last weeks to months) often show benefits like weight loss and stable blood sugar, while long-term observational studies (following people for years) frequently show concerning associations with weight gain, diabetes, heart disease, and death.
Why the disconnect? Short-term studies show what happens when you make a single dietary change in a controlled setting. Long-term observational studies capture the messy reality of real life, where many factors influence health outcomes. But those long-term studies also can't prove causation—they just show that two things occur together.
The reverse causation problem: People with health problems are more likely to use artificial sweeteners in the first place. So when studies find that diet soda drinkers have higher rates of diabetes or heart disease, we have to ask: Did the artificial sweeteners cause these problems, or did people who were already developing these conditions switch to diet products? This is called reverse causation, and it's incredibly difficult to untangle in observational research.
Different sweeteners, different effects: Not all artificial sweeteners are the same. They have "very diverse molecules with varied kinetics" (Ray & Palui, 2025)—meaning they're chemically different and your body processes them differently. Some research has found that certain sweeteners (like aspartame) affect the heart differently than others (like sucralose or acesulfame-K). But many studies lump all artificial sweeteners together, which may obscure important differences.
Individual variation: The personalized microbiome-driven effects of artificial sweeteners mean that different people may respond differently based on the unique community of bacteria living in their guts (Ray & Palui, 2025). What causes no problems for one person might affect another person differently.
Given all this uncertainty, what guidance do the experts offer?
The World Health Organization (WHO): In their 2022 comprehensive meta-analysis, the WHO found that (Ray & Palui, 2025):
The WHO's recommendation: Based on this mixed evidence, the WHO advised that "non-sugar sweeteners should not be used as a means for the prevention of non-communicable disease or controlling body weight" (Ray & Palui, 2025). In other words, don't use artificial sweeteners as a health strategy or weight-loss tool.
The FDA's position: The FDA maintains that artificial sweeteners are safe when consumed within the ADI limits. They recently reaffirmed that they see no safety concerns with aspartame when used under approved conditions (Ray & Palui, 2025).
The realistic middle ground: Ray and Palui (2025) conclude that "no strong evidence" definitively proves that artificial sweeteners cause cardiometabolic problems, but equally, no strong evidence definitively refutes this possibility. More long-term randomized controlled trials are needed to settle these questions.
In the spirit of transparency, let's be clear about what we still don't know:
Based on the research reviewed by Ray and Palui (2025), here are practical, evidence-based steps you can take:
1. Use artificial sweeteners as a short-term transition tool, not a permanent lifestyle solution. The evidence suggests that artificial sweeteners work best for short-term weight loss when you're actively trying to reduce calories—especially if you have a higher BMI and aren't already on a restricted diet. Think of them as training wheels to help you cut back on sugar, not as a permanent health strategy. The WHO's guidance is clear: they shouldn't be your long-term plan for weight control or disease prevention (Ray & Palui, 2025).
2. If you must use artificial sweeteners, consider stevia or sucralose first. According to Ray and Palui (2025), among the available options, "natural NNS stevia and synthetic NNS sucralose perhaps have relatively least concerning data." While no sweetener is perfect, these two appear to have fewer red flags in the research. However, keep in mind that sucralose has still been linked to some cardiovascular concerns in observational studies, so moderation remains key.
3. Pay attention to your total intake across all sources. Artificial sweeteners hide in many products beyond diet sodas—yogurt, protein bars, chewing gum, flavored water, condiments, medications, and "sugar-free" desserts all may contain them. While the ADI limits are quite high (you'd need to drink about 19 diet sodas daily to reach the aspartame ADI), it's still wise to be aware of cumulative exposure. Read labels and keep track of how often you're consuming products with artificial sweeteners.
4. Pregnant, nursing, or planning to become pregnant? Minimize artificial sweetener use. Given the 25% increased risk of preterm birth and the links to higher infant BMI (Ray & Palui, 2025), pregnant and breastfeeding women should practice "moderation" with artificial sweeteners until more research is available. When in doubt, choose water, milk, or small amounts of natural fruit juice instead. Always discuss dietary decisions with your healthcare provider during pregnancy.
5. Limit or avoid artificial sweeteners for children, especially under age 2. The guidelines are clear that children under 2 shouldn't consume artificial sweeteners at all (Ray & Palui, 2025). For older children, these products should only be used as part of an overall balanced diet—not as a daily default. Instead of training children's taste buds to expect intensely sweet flavors, gradually help them appreciate foods with natural, subtle sweetness or no sweetness at all.
6. Don't use artificial sweeteners as permission to eat more. One of the tricky things about artificial sweeteners is the psychological effect: when people save calories with a diet drink, they sometimes feel entitled to eat extra calories elsewhere. The research is mixed on whether artificial sweeteners increase appetite, but be mindful of your overall eating patterns. Track whether using artificial sweeteners leads you to compensate with extra snacks or larger portions.
7. Listen to your body and watch for personal reactions. Some people experience headaches (especially from aspartame), digestive upset, or taste changes from artificial sweeteners (Ray & Palui, 2025). If you notice negative symptoms after consuming these products, that's your body giving you valuable information. Keep a food diary if you're unsure whether artificial sweeteners are affecting how you feel.
8. Consider the plain alternatives. The research comparing artificial sweeteners to water or placebo often shows that the sugar-free options don't offer significant advantages over simply drinking water (Ray & Palui, 2025). If you're trying to cut back on regular soda, gradually transitioning to flavored sparkling water, herbal tea, or water with fresh fruit might be a better long-term strategy than switching to diet drinks.
Acceptable Daily Intake (ADI) — The amount of a substance (like an artificial sweetener) that regulatory agencies like the FDA consider safe to consume every day for your entire lifetime without health risks. It's measured in milligrams per kilogram of body weight.
Amniotic fluid — The protective liquid that surrounds a developing baby in the womb during pregnancy.
Artificial sweeteners (AS) — Synthetic or natural compounds that provide intense sweetness with little to no calories and are intended to be used instead of regular sugar. Also called non-nutritive sweeteners (NNS).
Atherogenic dyslipidemia — Abnormal levels of fats and cholesterol in the blood that promote the formation of plaque buildup in arteries, increasing cardiovascular disease risk.
Body Mass Index (BMI) — A measure of body fat based on your height and weight. It's calculated by dividing your weight in kilograms by your height in meters squared.
Carcinogen — Any substance or agent that has the potential to cause cancer.
Cardiovascular diseases (CVDs) — A group of disorders affecting the heart and blood vessels, including coronary heart disease, stroke, and heart failure.
Cerebrovascular events — Medical problems affecting blood flow to the brain, most commonly strokes.
Cohort study — A type of research that follows a group of people over time to see how different exposures or behaviors affect health outcomes. These studies can show associations but can't definitively prove cause and effect.
Coronary heart disease — A condition where the blood vessels supplying the heart become narrowed or blocked, reducing blood flow to the heart muscle.
Energy deficit — Consuming fewer calories than your body burns, which is necessary for weight loss.
EFSA (European Food Safety Authority) — The European Union's regulatory agency responsible for assessing food and food additive safety.
FDA (Food and Drug Administration) — The United States government agency responsible for protecting public health by ensuring the safety of food, drugs, and other products.
Gastrointestinal (GI) tract — Your digestive system, including your stomach, intestines, and all the organs involved in digesting food and absorbing nutrients.
Gut microbiota/microbiome — The trillions of bacteria, fungi, and other microorganisms living in your digestive system, particularly your intestines. These tiny organisms play important roles in digestion, metabolism, and immune function.
Hazard ratio (HR) — A statistical measure used in research to compare the risk of an event (like developing a disease) between two groups. An HR of 1.0 means no difference in risk; above 1.0 means increased risk; below 1.0 means decreased risk.
Hepatotoxicity — Damage to the liver caused by chemicals, medications, or other substances.
Incretin hormones — Hormones released by your gut after eating that help regulate blood sugar by stimulating insulin release and slowing digestion.
Insulin resistance — A condition where your body's cells don't respond properly to insulin, making it harder to control blood sugar levels. This can lead to type 2 diabetes.
Interventional study — Research where scientists actively change something (like giving people a treatment) and measure what happens. Randomized controlled trials are the gold standard type of interventional study.
Ischemic stroke — A type of stroke caused when a blood clot blocks an artery in the brain, cutting off oxygen and nutrients to brain tissue.
Ketonuria — The presence of ketones (chemicals produced when your body breaks down fat for energy) in your urine, which can indicate diabetes or other metabolic conditions.
MASLD (Metabolic Dysfunction-Associated Steatotic Liver Disease) — A condition where excess fat builds up in the liver in people who drink little to no alcohol. Previously called "non-alcoholic fatty liver disease" or NAFLD.
Meta-analysis — A study that statistically combines the results of multiple previous studies to get a more comprehensive answer to a research question.
Metabolism — All the chemical processes in your body that convert food into energy and build or repair tissues.
Non-nutritive sweeteners (NNS) — Another term for artificial sweeteners—substances that provide sweetness without significant calories or nutrients.
Observational study — Research that observes what happens to people based on their behaviors or exposures without the researchers intervening. These studies can identify associations but can't prove causation.
Preterm birth — When a baby is born before 37 weeks of pregnancy. Late preterm is 34-37 weeks; very preterm is before 34 weeks.
Prospective cohort study — A type of observational research that follows people forward in time, tracking their exposures and health outcomes as they happen.
Randomized controlled trial (RCT) — The gold standard of scientific research where participants are randomly assigned to different groups (like treatment vs. placebo) and outcomes are compared. This design helps prove cause-and-effect relationships.
Relative risk (RR) — A statistical measure comparing the probability of an event occurring in two different groups. Similar to hazard ratio—RR of 1.0 means equal risk; above 1.0 means increased risk; below 1.0 means decreased risk.
Reverse causation — When the effect appears to come before the cause. In artificial sweetener research, this happens when people switch to diet products because they're developing health problems, making it look like the diet products caused the problems.
Satiety — The feeling of fullness and satisfaction after eating that signals you to stop eating.
Steviol glycosides — The sweet-tasting compounds extracted from the Stevia rebaudiana plant that make up stevia sweeteners. Common types include stevioside and Rebaudioside A.
Systematic review — A comprehensive, structured review of all available research on a specific question, using rigorous methods to find, evaluate, and summarize the evidence.
Type 2 diabetes (T2D) — A chronic condition where your body doesn't use insulin properly (insulin resistance) and can't maintain normal blood sugar levels.
Ray, S., & Palui, R. (2025). Artificial sweeteners: Benefits, risks and controversy. Apollo Medicine, 22(3), 228–233. https://doi.org/10.1177/09760016251336000