Gastric bypass surgery radically improves subjects' gut biomes

Gastric bypass surgery is remarkably effective at promoting weight-loss (it cuts the long-term risk of early death from morbid obesity by 40%), and it's long been presumed that the major action by which it worked was that, by bypassing the parts of the gut where most food absorbtion takes place, it limited the calories that subjects' bodies could harvest from the food they ate. (more")