Is it possible that three very different chemical compounds that just happen to taste sweet, sucralose, aspartame, and saccharin, would all have the exact same biological effect on an animal? Only if you happen not to accept biology or chemistry, as happened in a recent Nature paper.
Ron Bailey at Reason was justifiably skeptical that a mouse model of the microbiome was really showing that fecal transplants with presumably altered gut microflora from affected mice to naive mice produced the same blood glucose spike so he consulted with American Council on Science and Health Director of Chemical and Pharmaceutical Sciences Dr. Josh Bloom, and you can read the results here.