Scientists studying yo-yo dieting in mice say the tendency for people to regain excess weight rapidly after successfully slimming may well be due to their microbiome - the trillions of microorganisms in the gut.

The researchers found that changes in the gut microbiome that occur when an obese mouse loses weight can persist for many months, and that this contributes to accelerated weight regain later if the diet lapses

Yo-yo dieting: getting to the guts of it Credit:iStock

If, as the researchers believe, a similar thing happens in obese people, they said, it could help explain why so many of them fail to keep their lost weight off, and often put on more than they lost in the first place.

In a telephone briefing about their work, professors Eran Segal and Eran Elinav of the Weizmann Institute of Science in Israel, said that while there has been good progress in studying obesity and its causes, relapsing obesity is poorly understood.