A high-fat diet during pregnancy has the potential to impair a baby’s developing brain and increase its chances of obesity later in life, animal studies suggest.Research carried out at  Yale School of Medicine, in the US, showed diet could change the structure of mice brains.This could be the reason why children of obese parents are more likely to become grossly overweight.Experts said the study had merit, but said brain changes in humans were unproven.Obesity can run in families and shared eating habits are a major factor.However, there is evidence that diet during pregnancy can also influence a child’s future waistline, such as through changes to DNA.The experiments on mice showed that mothers on a high-fat diet had pups with an altered hypothalamus, a part of the brain important for regulating metabolism.These mouse pups were more likely to become overweight and develop type 2 diabetes than the pups of mothers given a normal diet. One of the researchers, Prof Tamas Horvath, from Yale, told the BBC: "It could be a signal to the pup that it can grow bigger with plenty of food."It seems, at least, that this could have a major impact and we need to explore it further in both animal and human studies.”He says a healthy diet during pregnancy may help to break the cycle of obese parents having obese children.