Do sweeteners alter metabolism?

30 May 2010



Hi everybody, congratulations again on a great show, you're awesome. I have a question regarding metabolism.

I subscribe to a running magazine in which I found an article which stated that athletes should always avoid aspartame and sucralose (ingredients in zero calories sweeteners like nutrasweet and splenda) because they interfere with metabolism. It didn't say how!!

Probably they were talking about elite athletes, but it got me curious: if that is true (and please tell me if it is) calorie-concerned people who work-out and avoid sugar for the calories it has (favoring sweeteners) are probably dead wrong.

I will very much appreciate your help.

Thank you.
Emilio Romero
Guayaquil, Ecuador


Chris - I've seen some studies where they have looked at children, and also young juvenile rats who are being fed sweeteners or normal sugar. One suggestion that some people have made - I'm not sure whether the evidence for this is robust, but it sounds plausible - is if you feed juvenile rats on sweeteners, what happens is that the brain begins to misinterpret how many calories there really are in sweet things and it gets used to the fact that when you eat something which tastes that sweet and you don't get any calories for it, if you then do get into a situation where you can eat some sugary food, real sugar, sweet stuff, you then tend to over eat because the normal metabolic gate that would say, "I know how many calories I've taken in now because when I take in this level of sweetness, I normally get this number of calories." That's been thwarted by eating the sweeteners and as a result, it can lead to overeating and weight gain, and there's some evidence that people who are on these things for longer periods as children may then develop a habit or a sweeter tooth when they're older. But as I say, I think it's speculation. I'm not sure how plausible it really is. Interestingly, there's a paper that's come out this week. It's by Jay Slack who's over in America. They're actually looking at the bitter taste associated with sweeteners because you know when you eat something like saccharin, it has an aftertaste, and they found a chemical that they call GIV3727. The reason they call it that is because the real name of the molecule is 4-(2,2,3-trimethylcyclopentyl)butanoic acid. This blocks the receptor for bitter taste buds, so you could call it a bitter blocker, and as a result, things that were bitter tasting now taste sweet. So you can associate or accompany your sweetener with that molecule, and they've done it on humans, and people stop tasting the nasty bitter taste and they only taste the nice sweet taste. Isn't that nice?


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