I don’t just have a sweet tooth, I have a mouth full of them. About two years ago I cut out refined sugar from the places where I was obviously getting too much of it. Thus I now drink coffee and tea without sugar or sweetener, and I switched from my beloved Coca Cola to Coke Zero (Coke Light just tastes funny). However, the letter Tim Noakes wrote to give some more information on the low carb diet he is recommending, and also the Atkins diet and on most of the Atkins-like plans, forbid artificial sweeteners.

At first thought this didn’t make any sense to me, as most of them are non-nutritive and contribute no calories. Also the quantities you use are so small that I’d think it was a minor issue and well worth the enjoyment of having at least something sweet! So I went digging.

One of the concerns around sweeteners that I had heard of, and stored somewhere at the back of my head, was the question around them being carcinogenic. Luckily there are always university types, hungry to get another publication under their belts, who wade through all the literature available and present it as a consolidated review. This 2004 paper concludes that, although some sweeteners have been linked to bladder cancer in rats, this does not hold true in humans, and that:

…according to the current literature, the possible risk of artificial sweeteners to induce cancer seems to be negligible.

That paper has been widely referenced up until today, with hundreds of others also refuting any link between sweeteners and human cancer (beware, rodents shouldn’t drink diet cooldrinks!). So then there is the question of whether sweeteners contribute any calories or carbs to the diet. This becomes a bit messy since there are a lot of artificial sweeteners, and they appear in everything from baby food to frozen meals, diet drinks to medicines. They are roughly broken down into two categories, the first generation and now the new wave. A list of the ones in common use today can be found here, and this article provides a really quick history of artificial sweetness (not the kind you fake when talking to idiots).

What seems pertinent in this case is that the newer generation ones, like sucralose, are so ridiculously sweet (600 times that of sugar (sucrose), and a few times more than older generation sweeteners) that they are mixed with other ingredients to give them some bulk and also make them look like a sugar powder. The exact bulking agents used vary a bit by brand but dextrose and maltodextrin are common. And there you have it, the carbs sneak their way back in while we’re trying to satisfy our addiction to sweetness! Now because the serving sizes are so small, these sweeteners are classified as “free foods” on most diet programs, and can be labelled as zero calories due to legislation, but when we are having many servings of these, the carbs stack up. There are liquid versions which don’t use the bulking agents and may be a valid alternative.

But now diet cola doesn’t have any of these added carbohydrates, so what could the issue be? I don’t have a definitive answer on this, only a couple of theories and findings from research that has been done on sweetener use. Firstly, one of the big things with the low carb diet is to break the addiction to sweet, sugary foods, and keeping the sweetness in your diet, even if it is non-nutritive, is still stimulating the same neural pleasure pathways and reinforcing the addiction. Secondly, psychological effects such as cravings and taking in more energy through other sources, because you feel you have been so “good” and cut out sugar, can actually lead to weight gain from substituting sugar with sweeteners. Thirdly, and important especially for diabetics and those of us trying to maintain blood sugar to avoid the effects of yo-yoing levels, is something that I think is fascinating.

I stumbled across it half by accident, as I was thinking about how our Pavlovian response to food, such as salivating at the thought of it, causes us to react to the idea of food, before we have even swallowed. So I was looking at when insulin is released after eating. It turns out that some of the response of our body actually happens when we start chewing, and not when the food hits our stomach, intestines or bloodstream. This is known as the Cephalic Phase Response, and tells our stomach to release acids and digestive enzymes before the food arrives; a massing of the troops in preparation for the invasion. In addition to stomach acids, insulin is also released during the Cephalic Phase Insulin Response (CPIR) and this can be triggered not only by sucrose entering the mouth but also by some sweeteners, regardless of whether you actually swallow or not!

So there you have it, a very brief whirlwind discussion around artificial sweeteners. I don’t know if what I have found sways me one way or the other, but I hope it has given you a bit more insight into something that we usually think of as a perfectly innocent diet food. Personally, I am unlikely to stop drinking diet Coke, but after looking at the research I am going to be very aware of the “I can eat some more because I am only having diet drinks” syndrome, which I think I may be guilty of!