Since I’ve been on the topic of hormones and insulin release lately I thought this would be a good time to take a look at artificial sweeteners. What I want to look at is if using artificial sweeteners will cause our body to release insulin and if so if it’s similar to natural sweeteners. I know artificial sweeteners like aspartame and sucralose have gotten a bad rap, but lets face it they are everywhere including in most of the supplements we have come to love like whey protein, BCAAs and everyone’s favorite pre-workout drink. There are always options for more “natural” products, although usually at a hefty price.
Controlling how often insulin is released in our bodies becomes especially important when controlling or losing weight is the goal. While the release of insulin won’t completely shut down fat burning it will hamper the body’s ability to burn fat. Of course how much depends on how great of an insulin release there is. Obviously eating 100 grams of fast digesting carbs at once will slow things down much more severely than 10 grams of slower-digesting carbs, or even 10 grams of fast-digesting carbs. So how about those drinks that use artificial sweeteners to keep the calories and carbs to a minimum? Does the body still treat them the same or will insulin levels be kept low? Lets take a look, shall we?
First, I know there are a lot of things about artificial sweeteners to potentially be worried about. For the sake of this article, however, we aren’t going to worry about them and instead will focus solely on the potential release of insulin. We can save the rest for another day, which is entirely possible because from what I’ve seen lately research doesn’t necessarily back up everything we’ve heard. How’s that for a cliff hanger? Okay onto insulin release!
Glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) are released from the gut in response to nutrient intake and in turn stimulate insulin secretion. In a study published in 2009 in the American Journal of Physiology, Zucker diabetic fatty rats were given glucose or sweeteners orally. Plasma GIP levels increased significantly when they were administered glucose, but there were no increases in plasma GIP 30 minutes after any of the multiple artificial sweeteners they used. The artificial sweeteners had no changes in blood glucose levels and there was no increase in plasma GLP-1 concentration either. They were unable to find any evidence that artificial sweeteners acutely induce incretin release in vivo. (1)
In another study published in 2009 in the American Journal of Physiology 7 healthy human subjects were given either sucrose (table sugar) or the artificial sweetener sucralose. Once again GLP-1, GIP, blood glucose and insulin increased after sucrose but not after sucralose. This was consistent with reports showing no difference in subjects with type I and type II diabetes as well. (2) There are several other studies showing apartame and sucralose showing no affect on insulin release. (3, 4, 5)
Now, while there are several studies that show artificial sweeteners do not create a release of insulin, of course there are two sides to every story. In a recent study done at Washington University School of Medicine they tested severely obese subjects with a BMI greater than 42.3 who did not regularly consume artificial sweeteners and were insulin sensitive. Researchers compared sucralose ingestion in combination with glucose and water ingestion with glucose by having subjects undergo a 5-h modified oral glucose tolerance test. The sucralose ingestion group did have a greater incremental increase in insulin over the water group, however there were no significant differences in GIP or GLP-1. (6) The thing that is different about this study is they measured responses by combining glucose and artificial sweeteners. I’m not sure in what case this would happen in a real diet, but it appears to make a difference. I suppose if you were adding fast-digesting carbs to your whey protein post-workout this would happen, but then you obviously wouldn’t be concerned about insulin release either, would you? As we saw earlier, however, taking artificial sweeteners on their own do not create an insulin release. I don’t see any evidence convincing enough to think they do at this time.
Now, why is all of this important? Well for one if you are worried about insulin spikes from artificial sweeteners it sounds like you can stop worrying. The other is we’ve learned it’s probably best to wait a while before consuming your post-workout to allow the post-workout inflammation to do its thing. We also know that post-workout BCAA consumption is very important. My thought is if we can take in a BCAA mix right away post workout while avoiding an insulin spike our body can potentially start the healing process and stop the protein breakdown right away without getting much in the way of the inflammation process. Of course you could always do a BCAA drink with no flavoring at all, but trust me if you’ve never tried it before, it’s the most rancid tasting substance on the planet on its own. To me an ideal scenario for maximizing post-workout protein synthesis (you didn’t think I’d go this whole article with out talking about protein synthesis did you?) would be to take in a BCAA drink (note BCAAs only not whey protein) right after your workout, and then eat a meal or take in whey protein about an hour later. This is the protocol I will be starting now, that’s for sure.