Answer: Ditch the Artificial Sweeteners
One study in rats showed that aspartame, an artificial sweetener, reduced weight gain, but it also increased blood sugar and impaired insulin response. The rats fed aspartame also had higher Clostridium and Enterobacteriaceae in their intestines, both of which are associated with disease when present in very high numbers. Another study found similar results in mice and humans. It showed changes in the microbiota made artificial sweeteners have negative effects on blood sugar levels.