It appears that the type of microbes present in your intestine determine your blood sugar response to artificial sweeteners.
Hang on a second...aren't we supposed to be having no blood sugar response to artificial sweeteners? If they contain no calories, they don't convert into glucose, so shouldn't raise blood sugar, right? Well, last time I checked our bodies weren't simple little machines - many things impact blood sugar levels; not just calories in your food. Perhaps drinking kitchen cleaning fluid will also raise blood glucose levels - cleaning fluid also contains no calories.
Let me introduce you to two secrets in nutrition: 1. Calories are not the be all and end all...(well perhaps calorie counting is the be all and end all of a passionate relationship with food). 2. There is no such thing as a free lunch: You need to eat; for goodness sake make it high quality, mainly plant based, pleasurable and nutritious for body and soul.
Artificial sweeteners don't contain zero calories - your body just doesn't know how to get those calories out. So strictly speaking, you could say plastic or wood were calorie free too. But they don't taste sweet, so nobody bothers with them (want to knaw some wood instead of drink diet coke? Nope, didn't think so). Why oh why would you put something so artificial in your body? A teaspoon of sugar is not the reason you're facing overweight so please, allow yourself the luxury of something nutritionally recognisable a couple of times a day. If it is more than a couple of times a day, perhaps you're not sleeping/laughing/hugging/eating/drinking/pooing enough?
So it appears that the particular type of microbes which live in your intestine help to determine the blood sugar responses your body has to artificial sweeteners. Aspartame (yum!), sucralose (delicious!) and saccharine (can't cope with my cravings for it!) were all tested. These studies were very thoroughly performed in mice and people: some people had two to four fold increases in blood glucose in the short time following the consumption of the sweeteners. If your blood sugar is frequently running high, you are at a much higher risk of being diagnosed with diabetes.
Those little microbes may be mini, but there are a lot of them. There is power in numbers - build the right populations in your gut to prevent poor health. Your immune system is largely driven by your gut ecosystem: Eat a diet rich in plant fibres and for goodness sake, stay away from artificial sweeteners. If it is not food, it is not supposed to go in your mouth (don't we teach that once babies start crawling?).
See here for more information on the gut microbiome - fascinating! http://www.hmpdacc.org/.
News story: http://www.npr.org/blogs/thesalt/2014/09/17/349270927/diet-soda-may-alter-our-gut-microbes-and-the-risk-of-diabetes