Key Takeaways

  1. Nearly 60% of Americans consume more sugar than recommended, leading to various health issues like high blood pressure, obesity, and diabetes.
  2. Food scientists have researched sugar alternatives for decades. Aspartame, found in diet sodas and candies, is a popular sugar substitute.
  3. Diabetics favor aspartame as it allows them to enjoy sweets without affecting their blood sugar levels.
  4. In the 1960s, a chemist accidentally discovered aspartame’s sweetness while working on ulcer medications.
  5. Despite FDA approval, aspartame has faced allegations linking it to health issues like brain cancer and epilepsy. The WHO recently re-classified aspartame as “possibly carcinogenic”.
  6. Aspartame is 200 times sweeter than sucrose but contains roughly the same calories, making it a preferred choice for recipes.
  7. A study from Sao Paolo found that both sugary and aspartame-sweetened beverages caused insulin spikes, challenging the assumption that aspartame doesn’t affect insulin levels.
  8. The study suggests that diabetics might need to reconsider their use of aspartame due to potential unexpected insulin spikes.
  9. While aspartame is well-studied and deemed safe by many health organizations, this new study suggests potential risks. However, the risks of excessive sugar consumption are still considered greater.
  10. The WHO recently recommended against using non-nutritive sweeteners like aspartame for weight loss, suggesting they might not help and could even increase the risk of diabetes and cardiovascular complications.

Nearly 60% of Americans consume more sugar than the Dietary Guidelines for Americans recommend, and 20% of the average American’s caloric intake comes from straight-up sugar. Our sugar addiction has wrought serious consequences to our health nationally. Blood pressure, inflammation, obesity, fatty liver, and diabetes – you name it, excessive sugar consumption has its hands in countless chronic health conditions.

Unwilling to compromise, food scientists have spent decades researching alternatives to sugar that provide the same hit of sweetness without all the associated issues. Aspartame is a decades-old example of such a sweetener that has been pushed as the perfect answer to health concerns about sugar. Now found in diet sodas and candies around the world, aspartame is particularly enjoyed by diabetics who appreciate indulging in sweets without worrying about their blood sugar levels.

Unfortunately, new research is emerging that suggests aspartame may be another case of “too good to be true”. Read on to learn more about how a team of Brazilian researchers uncovered evidence that may complicate the picture when it comes to diabetics enjoying aspartame without worry.

A Brief History of Aspartame

Aspartame entered the food scene through unconventional means. In the 1960s, a chemist working on ulcer medications licked his finger while turning a page and found that it tasted incredibly sweet. The culprit was found to be aspartame, one of the intermediary compounds in the chemist’s project. Quickly thereafter, food scientists developed the obscure chemical into one of the most common and widely produced non-nutritive sweetener (NSS) food additives to ever hit the market. But aspartame’s rise to fame did not come without controversy.

While aspartame has been approved by the FDA – twice – and deemed to be safe by numerous health and safety agencies globally, controversial health claims have been leveled against the substance over the years. Accusations have been meted out by scientists, journalists, and critical organizations alike alleging aspartame’s role in brain cancer, epilepsy, impaired vision, and other neurological problems. Ultimately, the science has appeared to be settled in aspartame’s favor, for now – though the World Health Organization’s (WHO) recent re-classification of aspartame as “possibly carcinogenic” is rekindling old debates.

Aspartame owes its popularity to being 200 times sweeter than sucrose, despite containing roughly the same number of calories per gram. Recipes calling for an amount of sucrose can therefore instead use only a tiny fraction of that amount of aspartame and still achieve the same level of sweetness, but with negligible calories.

For dieters and diabetics alike, aspartame is an easy sell. Diabetics in particular must be attentive and disciplined about their sugar intake since their bodies cannot regulate their blood sugar levels naturally. Sugar hits can send them into hyperglycemia, a dangerous condition that comes with many health risks. Switching to artificially sweetened alternatives to their favorite snacks and soft drinks allows diabetics to satisfy their sweet tooth without any guilt or worry about the effects on their blood sugar. At least, this is the narrative that has tended to be pushed – but new research may cast doubt on its underlying assumptions.

The Sao Paolo Study

A university in Sao Paolo, Brazil, recently published a study scrutinizing the effects of aspartame on the body. The study, authored by Carolina Finassi et al. in the scientific journal Food Research International, investigated the effects that beverages containing aspartame, sugar, or no sweetener at all, would have on levels of insulin, aspartame, and other metabolic agents in saliva.

At the outset, aspartame was expected to not affect whatsoever on insulin levels. Insulin normally spikes in response to the intake of carbohydrates and the corresponding increase in blood sugar, but since aspartame-sweetened beverages contain virtually zero calories or carbohydrates, one would expect insulin levels to be unresponsive to aspartame. The actual results turned this hypothesis on its head.

Researchers gave a small group of healthy participants various carefully concocted test beverages: diet soda, regular soda, water with artificial sweeteners, sugar water, and plain water. After ingesting their respective concoction, each participant’s saliva was sampled and analyzed for its contents; specifically, for concentrations of protein, sugar-digesting enzymes, aspartame, and insulin.

A comparison amongst all beverages revealed no difference in salivary protein or enzyme contents but revealed significant findings for insulin and aspartame. Insulin levels spiked after sugary and aspartame-sweetened beverages alike, and salivary aspartame was detectable for an extended period following ingestion. The study also noted an apparent correlation between salivary aspartame and insulin levels, suggesting a causal relationship between aspartame consumption and insulin elevation. Salivary insulin levels correlate to serum (blood) insulin concentrations, making the findings indicative of systemic increases in insulin after consuming aspartame.

Clinical Implications

If the results of this study are accurate, they could require diabetics to rethink their choices around artificial sweeteners. Diabetics already work attentively to keep their blood sugar and insulin levels in balance as much as possible. This requires regular blood sugar monitoring and insulin administration, plus a careful consideration of what, when, and how much food is eaten. Insulin spikes occurring without a patient’s knowledge due to aspartame consumption could disrupt the careful balance of glycemic control and potentially worsen their blood sugar management efforts.

While insulin is critical for a healthy metabolism and is taken to treat diabetes, it is not a benign substance altogether. Excessive insulin can lead to a host of problems in healthy and diabetic patients alike, meaning that frequent insulin spikes (including, potentially, from products containing aspartame) may contribute to certain complications associated with elevated insulin. These can include weight gain, increased risk for cardiovascular disease, eye problems, kidney disease, and even stroke.

However, before drawing too many conclusions from the Sao Paolo results, it is worth noting that the study was limited in several relevant ways. For instance, the researchers studied a very small sample of people, most of whom were women, meaning that the results may not be replicated with a larger, more diverse population. And, the researchers noted their inability to control for the possibility that other ingredients found in diet sodas, particularly acesulfame, may also be playing a role in the results. Without rigidly controlling for this possibility, additional ingredients may confound the experimental results and lead to inaccurate conclusions about aspartame.

This study will hopefully serve as a useful launchpad to further research on the topic. The results may very well have challenged established notions about insulin response to artificial sweeteners, but the scientific community and consumers alike would benefit from a more exhaustive investigation into this study’s implications.

Implications for Consumers

So, what should a savvy consumer make of this new information? Should aspartame be avoided like the plague, or is this information just another insignificant controversy for an otherwise well-understood product?

In deciding how to respond to this new information, it may be helpful to keep a sense of perspective about the topic. Aspartame is a very well-studied compound that has been intensively reviewed and classified as safe by health organizations around the world. While this study may present problematic findings, there are several limitations associated with it that should limit the conclusions drawn from it.

And, if it’s going toe-to-toe with sugar in terms of overall health effects, the resounding evidence for sugar’s detrimental effects on many facets of our health cannot be understated. In other words, whatever risk may be associated with aspartame seems to be far smaller than the known risk associated with excessive sugar consumption. While the healthiest and most refreshing beverage choice will usually be good old-fashioned water, artificially sweetened beverages consumed in moderation are probably still a healthier alternative to sugary sodas.

Food for Thought: The WHO on Aspartame

On the topic of evolving understandings of aspartame, the WHO recently changed its stance on the utility of artificial sweeteners for weight loss. The organization released an updated guideline document in May 2023, recommending against the use of NSSs (including aspartame) to reduce the risk of obesity and other non-communicable diseases. The recommendations are based on a systematic review finding that NSSs have no long-term impact on body weight and may even lead to an increased risk of diabetes and cardiovascular complications in adults.

Importantly, the WHO’s guidelines applied to everyone except individuals with pre-existing diabetes and could not rule out the possibility that the results were confounded by behavioral patterns correlated with aspartame consumption, so diabetics may wish to take the findings with a grain of salt. Still, the publication of these new guidelines and that of the Sao Paolo results may signal a coming tone shift in attitudes toward aspartame.


Guidelines around healthy eating have a history of changing like the wind, and it’s no surprise that many consumers can feel confused and uncertain about what’s safe to consume. If you are unsure how to feel about recent updates, speaking to a doctor or dietitian about aspartame consumption is your best bet for obtaining informed guidance. You may also wish to stay current on guidelines from organizations like the WHO, which regularly publish public resources and health advisories that reflect their most current understanding of scientific evidence on subjects like aspartame consumption.