Artificial sweeteners have been used in the food industry for decades. The demand for them comes down to their sweet, satisfying taste minus the calories.
It is a bit like having your cake and eating it too. But there has been a lot of debate over the safety and efficacy of using artificial sweeteners.
Studies have explored the associations between artificial or non-nutritive sweeteners and a range of health outcomes including diabetes, cancer, gut health as well as changes to body weight.
However, the current pool of evidence is conflicting for the most part. We don’t really have a clear answer for any of these potential associations.
This post will explore the current evidence for the major claims regarding calorie-free sweeteners including the good and the bad.
Types of Low Calorie Sweeteners
One of the major issues with the research in the field of low-calorie sweeteners is that there are so many that could have completely different risks to one another.
Although all low or no-calorie sweeteners typically get thrown together and called artificial sweeteners, there are actually three main categories,
- Artificial sweeteners (eg. Sucralose, Aspartame, Saccharin)
- Sugar alcohols (eg. Sorbitol, Mannitol, Xylitol, Erythritol, Malitol)
- Natural low-calorie sweeteners (eg. Stevia, Allulose, Inulin, Monk Fruit, Tagatose)
Sugar alcohols are often found in sugar-free gum and confectionery as well as a lot of low-carb protein bars. They are not completely void of calories but are significantly lower than sugar.
Sugar alcohols can be found in many fruits and vegetables. But they are consumed in the largest quantities from sugar-free and reduced-sugar products.
The reason they are lower in calories than sugar is that they are not as well absorbed by the body.
From a calorie-intake perspective, this is great news. But high intakes of sugar alcohols can result in gas and abdominal pain and potentially have a laxative effect.
This is why you will see some diet products labelled with “excess consumption may have a laxative effect”.
One other important thing to note about sugar alcohols is that some of them, despite being low carb do raise blood sugar levels. It is not of the same significance as sugar, but a person with diabetes should be aware of this effect.
The most notable one is maltitol.
Natural Low-Calorie Sweeteners
The most well-known natural sugar substitute is stevia.
It is extracted from the Stevia rebaudiana plant that is typically grown in South America. Stevia contains sweet compounds that are 100 times sweeter than cane sugar gram for gram but with zero calories.
Monk Fruit extract is another natural sugar substitute with no calories. It has gained most of its popularity in the past few years.
Not too much is known about the long-term effects of high consumption of these products but they are often touted as the healthier and safer choice in comparison to artificial sweeteners.
Artificial sweeteners were actually developed by accident. Chemists were working on something completely different at the time. In 1877, a Russian chemist named Constantin Fahlberg unknowingly brought his work home with him when he took a bite of food that was surprisingly sweet.
He had actually spilt his experiment on himself and had eaten it by mistake.
So in complete serendipity, his research led to the creation of the first-ever artificial replacement for cane sugar and it just so happened to be calorie-free.
Since 1877, artificial sweeteners have had a rich history in the food industry.
Although the safety of artificial sweeteners is not clear cut and the majority of the research into potential harmful side effects are targeted at these types of sugar substitutes.
Calorie Intake and Appetite
The reason most people reach for non-calorie sweeteners is to manage their caloric intake and weight.
Sugar and sugar-heavy foods are typically a source of quickly digestible carbohydrates. They provide a significant number of calories without much satiating benefit.
Processed foods that have a high amount of added sugar such as confectionary and sugar-sweetened beverages (eg. soda) are typically easy to overconsume and their intake can contribute to weight gain.
It makes sense that if these products were available with much fewer calories due to the use of sugar alternatives, those who were weight or health-conscious would make the switch.
And for the most part, that has been a real phenomenon. Using low-calorie, diet products, particularly diet soft drinks have become a tool for weight management.
However, there is actually research to suggest that the consumption of diet products containing artificial sweeteners and sugar substitutes may actually be associated with weight gain.
Although it is important to note that research results on this topic are mixed.
A systematic review from 2019 included several studies that showed no association between non-sugar sweeteners and weight gain.
Upon further analysis, they even found that non-sugar sweetener use by overweight or obese individuals (that is, those not trying to lose weight) resulted in reduced body weight.
A consensus has not been reached on how the use of low or no-calorie sweeteners affects body weight long term.
One of the arguments used against low-calorie sweeteners is that they increase appetite and therefore increase overall caloric intake.
This notion started from a handful of studies in mice and fruit flies that showed an increase in calorie intake secondary to consumption of artificial or low-calorie sweeteners.
Several human studies have also shown a link between the consumption of some non-sugar sweeteners such as aspartame, acesulfame potassium, and saccharin and an increased appetite and heightened motivation to eat.
However, pooled data from four separate studies in humans showed a mean daily energy intake of just over 1000kj less a day in people consuming non-sugar sweeteners as opposed to sugar.
So despite data showing an increase in appetite, this may not reflect itself in an increased daily caloric intake.
Nevertheless, it is hard to say for sure that calorie-free sweeteners have any effect on energy intake or weight.
Perhaps as part of a holistic plan for weight management, they could be a useful tool for some.
Gut health is one of the lesser researched outcomes when talking about sweeteners. The research that has been done is still in its infancy.
The health of the gut microbiome is key to many aspects of human health including immune, metabolic and neurobehavioural traits. The best indicator of gut microbiome health is the diversity of the micro-organisms within it.
A 2014 study showed modifications in the intestinal microbiota after the administration of some sweeteners, particularly artificial sweeteners. The specific changes that occurred to the gut microbiota may actually even result in a reduction in glucose tolerance. This is particularly worrying since artificially sweetened food and drinks are typically recommended to those with or at risk of developing type 2 diabetes.
Based on current research of artificial sweeteners, only saccharin and sucralose shift the populations of gut microbiota.
Stevia may also affect the gut microbiota composition. But more studies are needed to verify this and determine the types of changes that may occur.
Finally, sugar alcohols, namely polyols, have had a fair bit of research behind them and their links to gut health and effects on the gut.
People with IBS tend to have adverse gastrointestinal reactions to the consumption of polyols. This is especially true for sorbitol and mannitol.
This is why the low fodmap diet for IBS management will temporarily remove foods high in polyols from the diet and reintroduce them to see if the individual reacts poorly
In addition to some people with IBS, sugar alcohols tend to have a laxative effect in most people in high quantities.
On the other hand, isomalt and maltitol, may have prebiotic actions and actually encourage improved gut health.
Some fluctuation in the gut microbiome has been seen with Xylitol intake. But these studies are currently limited to non-human studies including mice.
In general, the link between non-sugar sweeteners and gut health is not really known and more research is required.
Worries around artificial sweeteners specifically arose in the 1970s, when saccharin was shown to cause bladder cancer in laboratory animals.
This triggered further research into this space and saccharin was assessed for a link to bladder cancer in humans.
Human studies however have shown no clear link to bladder cancer to date.
Before its approval by the FDA in 1981, aspartame underwent several tests in laboratory animals to assess cancer risks. No adverse effects were found.
However, aspartame will likely forever have a tainted image due to a 2005 study that showed very high doses might cause lymphoma and leukemia.
Again, these research studies were done with rats. And the research was assessed by Food and Drug Administrations around the world who deemed the study unfit to provide conclusions that aspartame was unsafe for human consumption.
Sucralose, acesulfame potassium, neotame, and aspartame have also all undergone numerous safety studies including cancer risk studies. The results currently show no evidence that these sweeteners cause cancer.
Once again, a majority of this research was done on animals. It is impossible to say what the long-term cancer risk is from the frequent consumption of artificial sweeteners in humans. Since they have only been consumed on a widespread basis for less than 100 years, it is difficult to assess lifelong effects on health.
Overall, the research and evidence behind the use of non-sugar sweeteners is a mixed bag.
From the perspective of weight management, it is debated that low or no-calorie sweeteners possibly increase appetite but may also not increase total daily caloric intake. That in itself is a unique conundrum.
Some research even hints towards weight loss benefits in overweight and obese adults.
Artificial sweeteners specifically, over natural low-calorie sweeteners and sugar alcohols, seem to have the biggest question mark next to them.
Research in this space is continuing. As we have more population data we may see evidence to further back up or dispute debated associations between non-sugar sweeteners and various potential health outcomes.