Artificial Sweetners: Our Verdict

We get asked daily by our clients whether or not we recommend artificial sweeteners. The one word answer is no. People are often confused by this answer because they have heard from other dietitians, nurses, doctors, etc. that if they are trying to lose weight artificially sweetened foods are a healthy option to incorporate into their daily routine (with the exception of pregnant women, who shouldn’t be focused on weight loss anyway, but none the less should avoid them). Health Canada states on their website that artificial sweeteners can safely be a part of a healthy diet. Diabetes Associations recommend them, so why do we go against these organizations (which we turn to for guidance on many other issues)? Well, based on research studies we are simply not so convinced artificial sweeteners are doing what they were intended to do which is to help people lose weight.

This summer we had a dietetic intern student spend time with us and she had just finished a rotation where she did a project looking at the benefits of artificial sweeteners. I asked her if she had done a literature review on the association between artificial sweeteners and the impact they have on weight loss. She said she hadn’t and so I gave her the task of doing an up to date literature search on this topic. What she found completely shocked her and changed her opinion. I have summarized some of the recent papers we reviewed this summer.

In March of 2014 a research article was published in The American Journal of Public Health looking at diet beverage consumption and caloric intake among US adults. This study looked at data from the National Health and Nutrition Examination Survey during the years of 1999 to 2010. What they found was that overweight and obese adults who consumed artificially sweetened beverages actually had higher caloric intakes from food than overweight individuals who consumed sugar sweetened beverages.

The researchers theorize that when we consume sweet things like sugar it activates reward centers in the brain and makes us crave more sugar. Since the majority of artificial sweeteners are over 200 times sweeter than sugar, when people consume them they could provide an even greater reward than sugar causing a craving for sweet foods. Real sugar provides your body with calories allowing it to feel full. Artificial sweeteners on the other hand, increase your appetite for sweet tastes but do not provide any calories to the body. Therefore you still feel hungry after consuming them and hence crave for something more to satisfy you. This was a great study with lots of interesting theories; however, because it was strictly observational it cannot prove cause and effect.

Another study published in January of 2014 looked at the metabolic effects of artificial sweeteners in mice. Keep in mind results found in mice are not directly transferable to human beings, however, they do allow us to look at metabolic parameters and seek casual relationships that help us with determining studies to pursue in humans.

This study split obese mice into three groups, one group was given water to drink, one group was given sucrose to drink and one group was given artificially sweetened water to drink. All the mice were given the same solid food diet so the only difference was in what the mice drank. What they found was that the sucrose group had the highest weight gain, rise in blood sugar and insulin levels. This is not surprising as countless studies have linked high sugar intake with weight gain and diabetes. What was surprising was that artificial sweetener supplementation also significantly increased insulin, body weight, triglyceride (fat carried in your blood) and leptin levels (a hormone responsible for regulating our hunger levels) relative to the water group. This suggests that artificial sweeteners may actually cause insulin and leptin resistance. We can’t extrapolate the data directly to humans but it certainly leaves me asking the desperate question of when we can do this same study in humans because diabetics are most often the group artificial sweeteners are recommended for, and we need to determine whether or not artificial sweeteners have the same effect in humans.

The artificial sweetener group also had decreased levels of oxygen consumption and UCP levels. UCPs are mitochondrial transporters located in the inner mitochondrial membrane that are linked to energy metabolism. It is hypothesized this decrease in oxygen consumption and UCP levels reflected a reduced amount of energy the mice burned off. Again, extrapolating these results to humans is a huge jump and simply is not appropriate. It does however raise another question to be studied in humans- do artificial sweeteners slow down our metabolism? Could this explain why short term weight loss programs have seen success with artificially sweetened foods/beverages? They replace sugar sweetened foods/beverages with artificially sweetened beverages which results in less calories being eaten and, consequently, weight loss. However, after a prolonged period of time with continuous artificial sweetener intake, would metabolic rate decrease and individuals burn less calories than they did before, preventing weight loss and facilitating weight gain? This is a question we need researchers to answer for us with studies in humans.

These are just two of the studies we reviewed but the study on mice is one that has me asking a lot of questions. The intent of this blog was to make you think, but by no means can we take my questions and interpret them as evidence. The reason we do not recommend artificial sweeteners to our clients is because we are not satisfied with the evidence yet that supports its use. It seems like we approach things in the opposite fashion when it comes to our food supply, add new chemicals and pull them once we figure out they aren’t good for us. Call me backwards but I think we should figure out first if something is safe before we start adding it to our drinking water.


Bleich, S. N., Wolfson, J. A., Vine, S. & Wang, Y. C. Diet beverage consumption and caloric intake among US adults, overall and by body weight. American Journal of Public Health; 2014: 104 (3), e72-e78.

Mitsutomi, K., Masaki, T., Shimasaki, T., Gotoh, K., Chiba,S., Kakuma, T. & Shibata, H. Effects of non-nutritive sweetener on body adiposity and energy metabolism in mice with deit-induced obesity. Metabolism Clinical and Experimental; 2014: 63, 69-78.