Weight loss after gastric band surgery may be partly caused by changes to micro-organisms that live in the gut, say US researchers. A study in mice has shown that surgery causes different types of bacteria to colonise the gut.
Transferring samples of those bacteria into healthy mice caused them to rapidly lose weight without surgery.
But the Harvard University researchers said they could not yet explain the mechanism behind their results. There are differences in the bacteria in the stomachs and intestines of obese people compared with those who are of a normal weight.
And in people who have had gastric bypass operations to help them lose weight, the types of microbes that are found in the gut change.