Sugar substitutes linked to obesity | Nature
"A team led by Eran Elinav of the Weizmann Institute of Science in Rehovot, Israel, fed mice various sweeteners — saccharin, sucralose and aspartame — and found that after 11 weeks, the animals displayed glucose intolerance, a marker of propensity for metabolic disorders."
In the study, non-caloric sweeteners appeared to alter gut flora, triggering a decreased sensitivity to insulin. Insulin helps to drive glucose from the blood into the body’s cells, where it is used for energy. This change in sensitivity to insulin, aka glucose intolerance, causes elevated blood sugar and triggers weight gain.
The study was replicated in human volunteers, finding altered gut flora in 4 out of 7 subjects after intake of artificial sweeteners for just one week.
Suez J, Korem T, Zeevi D, Zilberman-Schapira G, Thaiss CA, Maza O, et al. Artificial sweeteners induce glucose intolerance by altering the gut microbiota. Nature. 2014 [ePub ahead of print] doi:10.1038/nature13793