Are Artificial Sweeteners Harmless? The Ultimate Truth About the Zero-Calorie Packets

You're better off skipping these sugar substitutes.

Packets of Equal and Splenda in a coffee bar in New York on Sunday, February 28, 2016. Artificial sw...
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If you enjoy your morning cup of joe infused with sugary goodness of the artificial kind, you might want to put down those packets of Sweet’N Low. In a new set of guidelines released this month, the World Health Organization is recommending folks avoid non-sugar sweeteners if they trying to lose weight or to prevent non-communicable diseases such as cardiovascular disease or cancer. The new guideline does not include new recommendations for people with diabetes.

The new guideline specifically warns against common non-sugar sweeteners like acesulfame potassium, aspartame, advantame, cyclamates, neotame, saccharin, sucralose, and even plant-based stevia and stevia derivatives.

While individuals with diabetes are exempt from this recommendation, it follows at the heels of a 2022 survey of all available studies on NSS, which “suggests that use of [non-sugar sweeteners] does not confer any long-term benefit in reducing body fat in adults or children.”

"Replacing free sugars with [non-sugar sweeteners] does not help with weight control in the long term. 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 press release.

Non-sugar substitutes like saccharin have been around for over a century but have grown in popularity over the last couple of decades due in part to the public demand for sweetness sans any health consequences.

So how dangerous are these fake sugars and do they provide any benefits at all? Let’s unpack what the science says about non-sugar sweeteners, some of which isn’t great but still largely unknown.

“This [recommendation] drives home the importance that there are no shortcuts to living a healthy life, there’s no magic bullet”

Are artificial sweeteners bad for health?

Non-nutritive sweeteners, also known as artificial sweeteners, are substances offering an equivalent taste and feeling of sweetness without the added calories of traditional sugar.

“Once they get into our gut, we don’t metabolize them for energy,” Nana Gletsu-Miller, an associate professor in applied health science at Indiana University’s School of Public Health-Bloomington, tells Inverse. “A lot of the times, [these non-sugar sweeteners] end up in the small intestine where they are not absorbed into the body or if they are, aren’t treated the same way [as traditional sugar].”

This means that non-nutritive sweeteners — because they don’t go down that pathway of turning into glucose — don’t rapidly spike blood sugar levels and subsequent physiological effects, making them an attractive dietary option for diabetics. And since there are no calories involved, you theoretically save yourself the inevitable guilt trip after snacking on sugar-free Oreos.

But research over the last several years has found that non-nutritive sweeteners aren’t exactly metabolically inert or benign once in our bodies. An August 2022 study in the journal Cell discovered that non-nutritive sweeteners can alter the gut microbiomes of healthy individuals, prompting unsettling changes in the body’s glycemic response when our gut bugs encounter these additives.

The changes aren’t limited to blood sugar. A February 2023 study published in Nature Medicine found that erythritol, a non-nutritive sweetener naturally present at low levels in fruits like grapes and pears and often added to ketogenic diet products, may increase one’s risk for stroke by promoting blood clots.

A more worrisome finding is that some of these effects could potentially transcend multiple generations. In a December 2022 study in the journal PNAS, researchers at Florida State University found that when mice drank water dosed with aspartame equivalent to 15 percent of the FDA’s recommended daily amount for humans over a period of eight to 12 weeks, the animals developed anxiety-like behavior. This was observed through changes in gene expression in the brain and when the mice were put through a variety of maze tests, says Pradeep Bhide, director of FSU’s Center for Brain Repair, who led the study.

“It’s not that mice had anxiety, but it was transmitted to two generations descending from the male mouse that received aspartame,” Bhide tells Inverse, through modifications in gene expression without altering the DNA itself, what’s called epigenetics.

It’s important to note what we see in mice may not necessarily translate to humans. But it does give cause to investigate whether non-nutritive sweeteners are capable of causing anxiety in us, which Bhide thinks is possible since aspartame breaks down into chemicals that can exert a neuropsychiatric effect.

While non-nutritive sweeteners might help you make better lifestyle choices, its still unclear whether the benefits outright trump the risks.

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But can they help with weight loss?

According to the World Health Organization, no. But there’s some nuance.

Gletsu-Miller says this recommendation was determined by looking at data from 283 randomized clinical trials — the gold standard when it comes to scientific experiments — and observational studies. Data from some randomized controlled trials seem to suggest that non-nutritive sweeteners may help with weight loss over a short period of time. However, long-term observational studies comparing individuals who consume non-nutritive sweeteners in their diet to those who do not consume them didn’t show significant weight loss in either group, with the former group often having a higher weight than the latter.

Because of these observational studies, Gletsu-Miller says the WHO was swayed to make their recommendation of advising against non-nutritive sweeteners for weight loss.

One major problem with observational studies such as these, Gletsu-Miller says, is that it's impossible to prove causation with them. She says it's possible that in these studies, people who have a propensity toward obesity are choosing non-nutritive sweeteners, not so much non-nutritive sweeteners are causing obesity.

The TL;DR? Whether non-nutritive sweeteners can help with weight loss is still very unclear. They could potentially help in the short term by slashing your usual caloric intake, but more research is needed to say anything about their effectiveness as a long-term weight management strategy.

Should you stop using non-nutritive sweeteners altogether?

If you’re someone with diabetes, non-nutritive sweeteners are better than turning to traditional sugar. But they aren’t a stand-in for healthy living, Ijeoma Isiadinso, medical director of the Emory Preventative Cardiology Program, tells Inverse.

“This [recommendation] drives home the importance that there are no shortcuts to living a healthy life, there’s no magic bullet,” says Isiadinso. “If we thought that artificial sweeteners were going to give us the reassurance of reducing your risk of cardiovascular disease, this is not the case.”

While non-nutritive sweeteners might help you make better lifestyle choices, only time will tell whether the benefits outright trump the risks. Isaidinso said you’re better off with a multifaceted approach to health — exercise, eating a diet low in red meat and high in fiber, avoiding smoking and excessive alcohol.

“This is the conversation I have with my patients. It’s not just sugar — now you’re using a substitute. But that wasn’t the only problem at hand,” says Isiadinso.

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