PARIS (AFP) - One in every two American adults will be obese by 2030, adding hugely to the countrys health costs, according to studies published on Friday that highlight the growing burden of the worlds obesity pandemic. On present trends, 50-51 percent of American men and 45-52 percent of American women will by 2030 have a body mass index (BMI) of 30 or more, adding as many as 65 million to the countrys population of obese adults, says one of the papers. Twenty-four million of these 65 million will be older than 60. The calculation extrapolates national estimates for 2007-08, the latest years for which data were available, when about 32 percent of American adults were obese. Britain, too, will see a surge in obesity prevalence, from 26 percent to 41-48 percent in men, and in women from 26 percent to 35-43 percent. By 2030, as many as 11 million more British adults will be obese, 3.3 million of them aged more than 60.