Artificial sweeteners fail to fool the brain

I’ve been attempting to catch up on some reading over the last few days, and this included skimming through the last couple of copies of New Scientist magazine. One article that caught my eye from the late December/early January issue concerned the effect of artificial sweeteners. In particular, the piece (by San Francisco-based writer Douglas Fox) makes the point that while artificial sweeteners may taste sweet, they fail to ‘satisfy’ the brain like sugar does. It is this mechanism that may explain, at least in part, the findings of some studies which find artificial sweeteners may cause individuals to consume more subsequently. And it might also help to explain why there really is no good evidence that artificial sweeteners promote weight loss.

The idea that artificial sweeteners may fail to trigger ‘satisfaction centres’ in the brain was the subject of a study I reported on in a blog back in September.

One of the studies cited in the New Scientist piece was covered in my blog [1]. This study found that in women given solutions containing either sucrose (sugar) or sucralose (Splenda) to drink, sugar activated the regions of the brain involved in registering pleasure more extensively than sucralose.

However, the piece also reported the results of an as yet unpublished study, which was similarly interesting. According to the New Scientist piece, the research, conducted by Paul Smeets at Utrecht University in the Netherlands, gave individuals a soft drink sweetened either with sugar or a blend of aritificial sweeteners (aspartame, saccharin, cyclamate and acesulfame potassium). Both drinks activated the brain, but only the one containing sugar caused part of the brain associated with reward (the caudate nucleus) to ‘light up’.

Here again, it seems, we have evidence that the brain can’t necessarily be fooled into thinking it’s had something it hasn’t (sugar). It seems the tongue can register sweetness from artificial sweeteners that does not transmit to the brain.

This, however, is not to say that sugar is somehow a great option either. It most certainly is not. And so what are our options? To my mind, the healthiest approach is not to have either refined sugar or artificial sweeteners. Now, some of us may view doing without sweet foods like some sort of hell on earth. This, in some ways, bears testament just to how addictive sweetness can be for some. And while many of us think of having a ‘sweet tooth’ as being something that is inherent within us, my experience is that this is not the case.

I have seen countless individuals break their addiction with sweetness. I explored this idea in a recent blog.

Quite often, a sweet tooth is rooted in chemical upset, for example unstable blood sugar levels. For advice on biochemically-based approaches to quelling sweet cravings, see here.


1. Frank GK, et al. Sucrose activates human taste pathways differently from artificial sweetener. Neuroimage. 2008;39(4):1559-69)

6 Responses to Artificial sweeteners fail to fool the brain

  1. Nicole 14 January 2010 at 7:10 pm #

    I find that stevia and even hibiscus or licorice root in herbal tea will provoke hunger if I’m fasting. Most hot drinks (other herbal tea, regular tea, coffee) usually *help* me maintain a fast.

    I keep seeing people saying that “but stevia is all natural, so it’s FINE, that other stuff is made of CHEMICALS and that’s why it messes you up.”

    What say you about “natural” zero-calorie sweeteners?

    I’ve banned stevia and AS from my life, and fruit sure tastes a lot sweeter now!

  2. Dr John Briffa 14 January 2010 at 7:19 pm #


    I generally advise against ‘natural’ zero-calories too, on the basis that they further perpetuate the desire or even ‘need’ for intense sweetness.

    Personally, now that I add little or no sweetness to the food I eat, I (like you) find naturally sweet foods taste much sweeter than before. More importantly, I very rarely get any desire for any more sweetness than is found naturally in foods.

  3. Chris 14 January 2010 at 10:14 pm #

    Oui d’accord, moi aussi ! !

  4. Nigeepoo 14 January 2010 at 10:19 pm #

    I’d rather have a bit of aspartame+acesulfame K or a bit less sucralose than either sucrose (tooth decay + higher TGs) or sour/bitter foods/drinks (Ewww!).

  5. RB 15 January 2010 at 9:19 pm #

    Never had a problem with Stevia sweetened drinks making me hungry. And our family consumes quite a bit of the stuff.

  6. Ian 15 January 2010 at 9:44 pm #

    Hello Dr Briffa,

    I was interested in Nicole’s comments, re Stevia.
    Could this be a personal reaction, ie, the addition of stevia to herbal teas promoting hunger whilst fasting, or are there other known instances where this effect has been noticed ?

    I ask as a Type 2 diabetic (who is trying to lose weight, a 13kg gain over 4 years ) and always use Stevia in coffee and teas. I have a BAD habit of late night snacking , after herbal teas, even after a good sized, 100% healthy meal.

    Your comments would be appreciated. Thank you

  7. Mariah Barnes 12 May 2010 at 12:26 am #

    i used Stevia extract as a sugar substitute because i am diabetic. Stevia is really sweeter than sucrose.~`;

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