“The artificial sweeteners aspartame, sucralose, and saccharin cause blood glucose abnormalities in mice and some humans, a team reports in an article published online in Nature (the world's most highly cited interdisciplinary science journal). The changes in glucose tolerance seem to be driven by the microbes in the gut and can be reproduced in germ-free mice by giving them gut microbes from a person who has consumed the sweeteners.
"We found that artificial sweeteners may drive...an exaggerated elevation in blood glucose levels, the very same condition that we often aim to prevent by consuming them," Eran Elinav, MD, PhD, from the Department of Immunology at the Weizmann Institute of Science, Rehovot, Israel, said at a press briefing.
A further experiment involving 381 non diabetic participants showed that long-term consumption of artificial sweeteners was associated with measures of central obesity and glucose intolerance, even when corrected for body mass index.
The authors caution that the results from the human experiments are not yet enough to make recommendations about whether or not people should consume sweeteners. They also point out that the mechanism for the sweeteners' effect is unknown: it may be causing less desirable bacteria to thrive, or it may be poisoning certain normal bacteria, allowing detrimental species to take their place.”
Based on the above, if you are adding artificial sweeteners or consuming them in soft drinks to avoid the effects of too much sugar it may be advisable to go completely sweetener free, as the result may end up being the opposite of what you are expecting.