"In the Israeli experiment, 10-week-old mice were fed a daily dose of aspartame, sucralose or saccharin. Another cluster of mice were given water laced with one of two natural sugars, glucose or sucrose.
After 11 weeks, the mice receiving sugar were doing fine, whereas the mice fed artificial sweeteners had abnormally high blood sugar (glucose) levels, an indication that their tissues were having difficulty absorbing glucose from the blood. "
So you feed group B sugar, and group A things that are not sugar, and then you put both groups through a glucose challenge, administering a calibrated amount of sugar, and group A's blood sugar spikes higher than group B's, which is not acclimated to metabolizing sugar. This is not surprising.
I suppose I'd need to read the journal article later when I have time, to be sure. There are a lot of things that look like interesting correlations in tests like this that actually aren't, when you control for all of the variables, and consider the short-term and long-term adaptations the body makes.