Lost Kilos Keep Coming Back? Gut Bacteria To Blame

Scientists studying yo-yo dieting in mice say the tendency for people to regain excess weight rapidly after successfully slimming may be due to their micro-biome – the trillions of micro-organisms in the gut. Researchers found that changes in the gut micro-biome 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. If a similar thing happens in obese people it could help explain why so many of them fall to keep their lost weight off, and often put on more than they lost in the first place. Professors Eran Segal and Eran Elinav of the Weizmann Institute of Science in Israel said that while there has been progress in studying obesity and its causes, relapsing obesity is poorly understood. People go on diets over and over again – and keep failing. It’s a very common problem. Up to 50% of obese people suffer this relapsing pattern to try to find out why, Segal and Elinav experimented with mice, giving them cycles of high fat diets interspersed with periods of lower fat normal diet. They found that the gut micro-biomes of the mice that lost weight were altered and that these changes remained in place for many months and contributed to rapid and excessive weight gain if the mice were given high fat diets again. The team has now begun exploring whether human gut micro-biomes respond in a similar way to those in mice, and whether treatments could be developed for it.