Are Artificial Sweeteners Making Us Gain Weight?
By: Tedi Nikova BASc, MPH ( c )
Artificial Sweeteners (AS) are a class of food additives, that add sweetness to food without adding any calories, also known as Non-Nutritive Sweeteners (NNS). Currently, the FDA has 6 artificial sweeteners approved, aspartame (Sweet’N Low), acesulfame- potassium (acesulfame-K), advantame, neotame, saccharin, and sucralose (Splenda). AS have a similar molecular shape to sugar molecules but are different enough so that the receptors on our tongue cannot recognize or break down AS to gain energy from them, making them 0 calorie options. Click here for further details on the molecular structure of AS. Back in the 1950s, there was excitement around the introduction of AS, and choosing AS over sugar-sweetened beverages was a no-brainer. However, with anything that seems too delicious in the health world, society has begun to question… is this too good to be true?
Why are they consumed?
Possible reasons some may choose artificially sweetened products include:
· Weight management and weight loss, AS have 0 calories, therefore substituting sugar for AS can reduce your daily caloric consumption.
· Diabetes management, Since AS is not digested, AS should be an ideal choice for individuals with diabetes, as AS should not cause a rise in blood sugar, allowing those with diabetes to still enjoy sweet food and beverages.
Possible negative side effects
Weight Gain
A number of smaller cohort studies have linked AS intake to weight gain. Longer-term epidemiological studies have shown that NNS might increase the risk of weight gain and metabolic syndrome. However, these studies were observational therefore cause and effect can not be determined. Overall Randomized Control Trials (RCTs) show that swapping artificial sweeteners for sugar has actually been shown to reduce weight, as AS reduces total caloric intake compared to beverages sweetened with sugar. A 2019 systematic review showed a handful of RCTs demonstrated no significant changes in body weight in adults consuming AS beverages compared with those using sugar or placebo (water), however, AS intake by overweight and obese individuals resulted in significant weight loss. In a 2014 meta-analysis of RCTs and prospective cohort studies, a modest but significant weight loss was observed from those consuming AS beverages compared to those consuming sugar-sweetened beverages, however, the studies concluded that AS as a mean source of weight loss intervention is not sufficient for significant weight loss, other lifestyle considerations must be made in order to achieve significant weight loss.
Eating Behaviour
The theory of why AS may increase food consumption is that sweet receptor may not be registering AS, as the satiating as the food-reward pathway is not triggered as stated in a 2018 systematic review. However the evidence is finding the opposite, in a 2019 systematic review calorie intake and appetite from 4 RCTs showed a significantly decreased calorie intake from those consuming AS versus sugar or placebo (water). Additionally, the pooled effect from 2 RCTs in overweight adults demonstrated that the desire for sweets was slightly lower in those receiving AS. A 2017 review found one systematic review that concluded an appetite lowering effect of AS while the other four systematic showed conflicting results.
The Gut
It is speculated that long term use of artificial sweeteners dysregulates and reduces the diversity of gut microbiota. It is not clearly understood how artificial sweeteners affect the gut microbiota, it is hypothesized this is due to metabolites from AS breakdown, these affect some individuals more than others, due to differences in gut microbiota. Reduction in diversity has been linked to several diseases including obesity, type 2 diabetes, and several inflammatory conditions, study results can be found here. A 2015 review study argued that depending on an individual's gut microbiome someone can be more or less sensitive to microbial changes.
Diabetes
AS development was driven mainly by giving diabetes patients an option to consume sweet beverages without spiking blood sugar. However, in recent years, there has been speculation if they truly do not impact blood sugar. In a long term observational study the risk of development of type 2 diabetes was 67% elevated, compared to nonconsumers. In a 2019 systematic review, two RCTs showed that those receiving AS were slightly lower blood glucose than those receiving sugar, however, no differences in insulin or insulin resistance were observed between groups. More research is needed on this topic, as the research available that shows an association of diabetes and AS intake is largely observational, therefore we do not know if AS actually have an impact on the risk of diabetes, or other factors may be pre-disposing those individuals who are consuming more AS, for increased risk of diabetes.
Cancer
In the 1990’s it was hypothesized that AS is a carcinogen that is associated with cancer risk, especially bladder and urinary tract cancer. A 2017 review concluded that there was not enough sufficient evidence to link artificial sweeteners to increased cancer risk. In a meta-analysis of case-control studies of artificial sweeteners, there was an association of increased reported intake of AS and bladder and urinary tract cancer risk, however, these studies have been refuted, and there is a large evidence base to state that there is no link between consumption of AF and cancer risk.
To sweeten or not to sweeten?
It is important to be aware that a lot of the current research exploring the effects of AS intake is largely observational studies, comparing individuals who consume v.s who do not consume AS therefore it may be likely that those who are consuming more AS intake may just be more likely to develop type 2 diabetes or obesity due to other lifestyle or genetic factors. The evidence is pointing to unclear conclusions for the health benefits of AS, and the potential harms cannot be excluded. There is still more research needed for some of the potential harms of AS.
It is important to also be aware that there is a “ health halo” around “sugar-free” items. Individuals may be more inclined to over-consume these products as they may be viewed as healthier due to their higher sugar counterparts. However, it is important to still be aware that sugar-free foods and beverages do not replace more nutrient-rich whole foods. The Nutrition Academy of Nutrition and Dietetics concluded that artificial sweeteners can be a good alternative for added sugars, in which there is research to suggest negative implications for excessive added sugar intake. Recommendations continue to be to speak to a registered dietitian to ask any questions about the health effects of AF, click here for the full position statement from the Nutrition Academy of Nutrition and Dietetics.
Another option is natural sweeteners, these sweeteners are naturally derived from plants, and are not made artificially, these include sugar alcohols (Eg. Xylitol, Dextrose), stevia and newly popular monk fruit. In 5 randomized control trials, stevia had no significant impact on weight, however, the majority of studies were of small sample sizes, and varying doses, lower blood glucose post meal compared to stevia. v.s placebo (sugar). The use of sugar alcohols and stevia has been reported as safe by Health Canada. There is however limited research on natural sweeteners, however, for those with Irritable Bowel Syndrome (IBS), or sensitivities, sugar alcohols are fermentable in the gut and can cause uncomfortable feelings of bloating and gas.
The lesson learned from the research is that AS are SAFE! However, with any food or drink, they should be consumed in moderation.
