We've updated our Privacy Policy to make it clearer how we use your personal data. We use cookies to provide you with a better experience. You can read our Cookie Policy here.


Artificial Sweeteners: The Good and the Bad

A mug and sweetener.
Image credit: iStock
Listen with
Register for free to listen to this article
Thank you. Listen to this article using the player above.

Want to listen to this article for FREE?

Complete the form below to unlock access to ALL audio articles.

Read time: 3 minutes

Sugar makes life that little bit sweeter, but its taste can come at a calorific cost. That dusting on your cereal, that white cube in your tea – these little dashes of the sweet stuff can add up to more than just weight gain; if consumed in large enough amounts over years, sugar can contribute to serious conditions like diabetes and heart disease. It’s little wonder, then, that many consumers in recent years have ditched sugar in favor of artificial sweeteners, some of which boast zero calories.

But are these fabricated flavorings really any better for us? Well, they have their good and bad qualities, according to the latest research.

The good

Many people opt for artificial sweeteners to help them lose weight, and there is some research to show that the sweeteners can help shift the pounds.

One study found that young adults who replaced their regular soft drink with a sugar-free version lowered their body mass indexes (BMIs) by 1.3–1.7 points, on average.

A meta-analysis of 15 randomized controlled clinical trials also concluded that low-calorie sweeteners are associated with modest decreases in body weight and fat mass.

Other sweetener-obesity studies, however, have come to different conclusions, but we’ll come to that research later…

As for other benefits, one 2018 study found that the sweetener saccharin has a strong affinity for a protein associated with aggressive cancers. At the time, the researchers said that the flavoring could one day form the basis of a more selective cancer therapy.

A more recent study found that, in test tube experiments, a novel artificial sweetener increased the levels of beneficial human gut microbes such as Bifidobacterium and Lactobacillus.

And when it comes to sustainability, some artificial sweeteners may just have the advantage. A study published last year found that stevia sweeteners produce around 10% of the greenhouse gas emissions of sugar. 

The bad

While most health authorities consider sweeteners, on the whole, safe to consume, recent research has highlighted some of the flavorings’ unsavory effects. 

Many studies have linked the sweeteners to a higher risk of cancer, for instance. One recent paper found that survey participants who consumed larger amounts of aspartame and acesulfame-K had an increased overall risk of cancer compared to non-consumers.

These kind of findings led the World Health Organization to infamously list aspartame as a “possible carcinogen” last July.

Other studies have observed a link between the sweeteners and an increased risk of cardiovascular diseases.

One paper, published last year in Nature Medicine, observed that patients who had experienced heart attacks and strokes were more likely to have elevated levels of the sweetener erythritol in their blood. After experimenting with the flavoring in the lab, the researchers seemingly proved that the sweetener did make human platelets easier to activate and clot, fostering “enhanced thrombosis.”

When it comes to behavioral effects, several studies have linked sweeteners to nervousness. One experimental study published last year found that aspartame produced anxiety-like behavior in mice.

“We believe that aspartame produces a shift in the excitation-inhibition balance, in favor of excitation,” Pradeep Bhide, Chair of Developmental Neuroscience at Florida State University College of Medicine, told Technology Networks at the time.

And as for obesity, while several trials have linked use of the sweeteners to modest decreases in body weight and fat mass, other studies have found the opposite effect. One paper published in 2016 found that that artificial sweeteners mimic a starvation state in the brains of fruit flies, causing them to seek energy by eating more food.

This kind of contrary research led the WHO to take a fairly neutral stance on the sweeteners’ dietary benefits last year. After accepting recommendations of a recent systematic review of the research, the health organization said that use of the sweeteners “does not confer any long-term benefit in reducing body fat in adults or children.”

“People need to consider other ways to reduce free sugars intake, such as consuming food with naturally occurring sugars, like fruit, or unsweetened food and beverages,” Francesco Branca, WHO Director for Nutrition and Food Safety, said in a statement last May.

“NSS [non-sugar sweeteners] are not essential dietary factors and have no nutritional value. People should reduce the sweetness of the diet altogether, starting early in life, to improve their health.”


So, are artificial sweeteners good or bad for us? Well, if successfully used to wean a person off high-calorie, sugary treats, the flavorings could incur some health benefits (albeit with possible nervousness side effects). But health authorities like the WHO aren’t convinced these benefits occur in practice.

Ultimately, consumers may be best off taking the organization’s advice and limiting the sweetness in their diets altogether, as difficult as that may be.