"We're still looking into what proportion of them may have had severe -- morbid obesity or extreme obesity, " she said.

CNN: Study: Underlying conditions playing less of role in H1N1

In the USA the percentage of black women with morbid obesity - a BMI of 40 or more - has doubled in less than a decade to 15%.

BBC: Obesity epidemic tops 1.7bn

"They were 'sold' to the IOC members as the IOC's low-cost contribution to sedentary lifestyles among the youth of the world and morbid obesity, " said Richard Pound, an IOC member from Canada who lost against Rogge in a bid for the group's presidency.

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