T Nation

Splenda and Insulin


As a consumer of diet coke, I am curious as to the effects of sugar substitutes on my insulin levels. I drink a diet coke/day. What effects if any does the aspartame have on my insulin? What effects if any does the caffiene with aspartame have on metabolism?


While there are loose theories on the correlation found between ingestion of artificial sweeteners and obesity, there is no evidence I have seen (though evidence may exist) of aspratame (which is in Diet Coke) to affect insulin.

Some basic studies for your reading pleasure:





Avoid aspartame if you can. The FDA has received numerous reports of seizures and other problems. It may also be a neurotoxic. Common side effects are dizziness, visual impairment, disorientation, ear buzzing, a high level of SGOT (liver enzyme), loss of equilibrium, muscle aches, episodes of high BP, headaches, mood disturbance, and fuzzy thinking.

Other people, called 'aspartame responders', can get an addiction to aspartame. Kathleen DesMaisons, PhD (an expert in addictive nutrition), believes that the taste of any sweetener, for sugar-sensitive people, evokes a beta-endorphin response in the body which will create cravings.

Saccharin: had a reputation for cancer-causing in rats because rats got bladder tumors when they were fed high amounts (equivalent to what a human would get drinking 800 cans of diet soda a day). So it's safe, in reasonable amounts. A top choice, along with sucralose and stevia.

Cyclamate: also had a cancer-causing reputation in rats. Safe in small amounts.

Acesulfame-K: same family as Saccharin, not widely available in the states.

Sucralose (splenda): the chemical alteration prevents the digestive system from "recognizing" it, so it doesn't cause the rise in blood sugar and insulin associated with sucrose, unless of course it turns out to cause an insulin rise through a conditioned response mechanism. The problem with Splenda (theoretically), is that the chemical "alteration" involves adding chlorine molecules. The situation is evolving, but apparently this choline molecule has a lot of concerns.

Erythritol: natural sugar alcohol, no GI impact, tastes great. Most promising artificial sweetener, be on the look out for companies marketing this.

Stevia: No downside since it's an herb, but it has a weird aftertaste that some people don't like.

Credits to Jonny Bowden and his "Living Low Carb" book for this info.

I drank a movie-sized medium Diet Coke while typing this.


Most important part of this post.


wow interesting stuff. ur a smart cookie andy :slightly_smiling: what do u do? cos u gave me some advice on my injury as well didnt ya


As I was told by my coach: "sweetners and fake sugars cock block fat loss." But people like Shug and Starnes get away with it (and others) so......I cut it out just for the sake of the convo.



I was always told that artificial sweeteners weren't rising insulin, because they are not carbs.

However, from my personnal experience, It is different.

For the exact same Whey protein powder, one with sucralose and one without, from the same brand (same product), the one with sucralose in it makes me feel dizzy, something that I suppose is hypoglycemia.
It does not happen at all with the sucralose-free protein powder.

Of course that is my own anecdotal feeling, nothing scientific here.
If it has nothing to do with insulin, I would be interested by an explanation.



Moderation is key. 1 diet coke a day will do nothing wrong to you i believe


nah I just read a lot of stuff and these topics pop up all the time on T-Nation, so I just refer back to my book.


Splenda (sucralose) has the most safety testing of any artificial sweetener. If the 'situation is evolving' then that's breaking news. Please explain.

"...sucralose does not break down or dechlorinate.[31] The chemistry of organochlorides differs from that of inorganic chlorine salts. Therefore, comparisons of sucralose to the safety of chloride salts, such as those made by the International Food Information Council (IFIC),[32] are not relevant."


Ace-K (Acesulfame Potassium) is an ingredient in a lot of protein powders and protein drinks. Almost everybody reading this has already eaten it, probably.

What year is the publication of this nutrition textbook you're quoting from? If it's more than 5 years old, maybe you should put it in the recycling bin. Science textbooks can be regularly outdated.


It's not a nutrition textbook. Jonny Bowden's Living Low Carb book from 2003, so it is a bit dated.