Weight loss after gastric band surgery may be partly caused by changes to micro-organisms that live in the gut, say US researchers.

Traditionally, weight loss surgery is known to work through “restriction” and in some cases “malabsorption”. Recently bypass surgery has been found to alter the level of chemical transmitters that arise from the gut to lead to an early fullness and decreased craving. The article above suggests a fourth mechanism, which is the alteration of gut bacteria following surgery and leading to weight loss. This lends further support to the effectiveness of surgery in achieving weight loss.