The longer immigrants stay in the United States, the fatter they become, according to a study published in the Journal of the American Medical Association.

Research showed that less than one-in-ten newly arrived immigrants is obese but at least 15 years in the US the number shoots up to one-in-five, roughly the same rate for Americans born in the country.

Dr. Christina Wee, co-author, said that immigrants are less likely to be well advised on diet control and exercise from their doctors than established citizens. However, immigrants are healthier on average than native-born Americans because the strain involved in emigrating discourages weaker and sick people from moving.