Artificial Sweeteners: Do They Help You Lose Weight or Gain it? Are they Safe?

Farmin Shahabuddin, MPH, Laura Gottschalk, PhD, and Amanda Chu, National Center for Health Research

When people want to treat themselves to something sweet without having to treat themselves to a larger pants size too, they often reach for low-calorie, artificial sweeteners. But do artificial sweeteners actually help you lose weight? The answer is not necessarily. As for their safety, the answer becomes more complex.

What are Artificial Sweeteners?

The most popular types of sugar substitutes in the US and many other countries are artificial sweeteners. Artificial sweeteners are typically made in a laboratory and don’t contain calories or supply your body with energy, vitamins, or anything else nutritious. These sweeteners are many times sweeter than sugar, so less is needed to reach the same level of sweetness as something containing sugar. Sweeteners can be used in the home for baking and cooking, and they can also be found in soft drinks, candy, and canned foods that are not necessarily sweet. These artificial sweeteners are considered to be “ultra-processed” and in addition to being used as sweeteners in foods that are marketed as “low-sugar” or “sugar-free” are also used to mask the taste of preservatives or other ingredients in foods that are not sweet.[1]

There are six types of artificial sweeteners currently approved by the FDA.

Two “natural” sugar substitutes have also been approved by the FDA. Brand names such as Truvia, PureVia, Enliten (Steviol glycosides), Nectresse, Monk Fruit in the Raw, PureLo (monk fruit extract) are all made from plants. But before being sold in the store, they must first be highly processed in a laboratory. So don’t be fooled into thinking that the word “natural” means that it comes straight from nature to your table.

Do Artificial Sweeteners Help You Lose Weight?

grocery shopping and soda

It makes sense that eating and drinking fewer calories by switching to sugar substitutes should lead to weight loss. However, there are several studies that found that people who drink diet drinks weigh more than those who don’t.[2] However, that does not mean that the sugar substitutes cause weight gain, since people who are overweight may choose diet drinks in an effort to lose weight.

Researchers are questioning whether these products may actually make it more difficult to lose weight, perhaps because sweet drinks and foods make people crave more sweets.  For example, research published in 2021 found that drinking beverages sweetened with the artificial sweetener sucralose, led women and people with obesity to eat larger amounts of food at their next meal.[3] That would definitely stand in the way of people trying to lose weight.

The best way to study if artificial sweeteners help people lose weight is known as a randomized controlled trial. People in the trial would be randomly put into groups—one group uses artificial sweeteners while the other group uses sugar. Then, the two groups can be compared to see if using artificial sweeteners had a different impact than sugar. However, randomized clinical trials would be very difficult to conduct on artificial sweeteners because they are in so many different types of food, not just diet drinks.

In 2023, the World Health Organization (WHO) scrutinized scientific reviews of the effect of artificial sweeteners on weight control and concluded that artificial sweeteners do not help people lose weight.[4]

Are Artificial Sweeteners Safe?

A 2020 study published in the journal Cell Metabolism by a group of Yale researchers found that the consumption of the common artificial sweetener sucralose (found in Splenda, Zerocal, Sukrana, SucraPlus) in combination with carbohydrates can turn a healthy person into one with high blood sugar.[5]

You may have heard claims that artificial sweeteners could change hormone levels [6], increase the risk of heart problems [7], and cause higher rates of type II diabetes.[8] An important 2022 French study of more than 100,000 adults followed for a median of 9 years found that consuming artificial sweeteners was associated with a very slight increased likelihood of experiencing newly diagnosed cardiovascular conditions such as heart attacks and stroke. The study identified three artificial sweeteners that seem to cause the greatest increases. People taking aspartame (NutraSweet, Equal) were more likely to have a stroke, while people taking acesulfame potassium (Sunnett, Sweet One) or sucralose (Splenda) were more likely to develop coronary artery disease.[9]A follow-up study of the same French adults, published in 2023, found that people who consumed the most artificial sweeteners were also more likely to develop type 2 diabetes than those who consumed none. This was also true when each of these three types of artificial sweetener was evaluated separately.[10]

The reasons why artificial sweeteners might harm cardiovascular health are unclear. However, experts suggest that these sweeteners could increase inflammation, metabolic disruptions, and alterations in the gut microbiome and blood vessels. That may increase the chances of developing conditions such as type 2 diabetes, unhealthy cholesterol levels, and high blood pressure.

There is increasing evidence that these sweeteners are harming healthy bacteria in the gut. In a 2022 trial, 120 healthy adults who did not normally use artificial sweeteners were given small daily amounts of sucralose, saccharin, aspartame, or stevia for two weeks, all below the daily limit set by the FDA. Sucralose and saccharin raised participants’ blood sugar after meals and changed which bacteria were present in the gut.[11] By 2026, when experts combined the results of many studies, they found that artificial sweeteners raise insulin and a marker of long-term blood sugar called HbA1c. Higher insulin over time can be an early sign that the body is having trouble managing sugar, which can lead to type 2 diabetes.[12]

A newer concern involves erythritol, a sweetener often labeled as “natural” and found in many stevia and monk fruit blends, as well as in “keto” and “sugar-free” foods. A 2023 study found that people with higher levels of erythritol in their blood were more likely to have a heart attack or stroke in the years that followed. In laboratory tests, erythritol made blood platelets stickier and more likely to form clots, which can block blood flow to the heart or brain. Eating a single serving of erythritol raised blood levels far above the point where this clotting effect begins, and levels stayed high for more than two days. Since erythritol is now so common, experts say more research is urgently needed.[13]

Artificial sweeteners also increase the chances of being depressed, according to a study published in 2023 on 31,712 women aged 40-62. After statistically controlling for other traits such as age, smoking, and BMI, women who consumed larger quantities of artificial sweeteners and artificially sweetened beverages were more likely to be depressed. While the reasons are not fully understood, the use of these artificial sweeteners can lead to changes in the brain that could contribute to the development of depression.[14]

For many years, there were concerns about whether artificial sweeteners cause cancer. A recent study by the WHO’s International Agency for Research on Cancer (IARC) has found a possible link between aspartame and liver cancer. While the risk of cancer from aspartame is considered low for most consumers, those who consume large quantities could be harmed. In addition, children may reach the daily recommended limit more easily due to their lower body weight. In fact, a 44-pound child would only need to drink approximately four cans of Diet Coke per day to exceed the maximum recommended limit. That is why it is so important to be very careful to consume as little aspartame as possible, especially for children, to reduce the chances of developing cancer.[15]

Should You Use Artificial Sweeteners?

Does the increased risks of obesity, diabetes, and heart disease from consuming large amounts of sugary drinks may outweigh the risks posed by artificial sweeteners?  That is still now clear, but based on the research so far, it makes sense to avoid the largest drink sizes, whether sugary or artificially sweetened. There is growing evidence that consuming even small amounts of artificially sweetened beverages may result in similar health risks to sugary drinks, and they apparently do not help with weight loss. Finding healthier alternatives, such as making your own coffee or tea, or flavoring water with slices of lemon, lime, watermelon, or apple, is a good strategy for your health. And, keep in mind that you should never consume more calories in other food because you “saved” some by drinking a non-caloric drink![9]

All NCHR articles are reviewed and approved by Dr. Diana Zuckerman and other senior staff. 

The National Center for Health Research is a nonprofit, nonpartisan research, education and advocacy organization that analyzes and explains the latest medical research and speaks out on policies and programs. We do not accept funding from pharmaceutical companies or medical device manufacturers. Find out how you can support us here.

References

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  3. O’Connor, A., Steckelberg, A., & Reiley, L. (n.d.). How fake sugars sneak into foods and disrupt metabolic health. Washington Post. Retrieved January 11, 2024, from https://www.washingtonpost.com/wellness/interactive/2023/sugar-substitutes-health-effects/
  4. The World Health Organization. WHO advises not to use non-sugar sweeteners for weight control in newly released guideline. May 2023. Retrieved from https://www.who.int/news/item/15-05-2023-who-advises-not-to-use-non-sugar-sweeteners-for-weight-control-in-newly-released-guideline
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  14. Samuthpongtorn C, Nguyen LH, Okereke OI, et al. Consumption of Ultraprocessed Food and Risk of Depression. JAMA Netw Open. 2023;6(9):e2334770. doi:10.1001/jamanetworkopen.2023.34770
  15. Florko, Nicholas. WHO says aspartame might cause cancer–but that most adult consumers don’t need to worry. STAT. July 13, 2023. https://www.statnews.com/2023/07/13/who-says-aspartame-might-cause-cancer-but-that-most-adult-consumers-dont-need-to-worry