Excellent point, and good luck trying to sort out and explain all the tangled host of things that factor into the reasons for that. People in the Majority World shake their heads over the phenomenon that in the US, the poor are more likely than the rich to be fat!
It is hard to explain how empty, fattening calories are so much cheaper, so much more accessible to the poor than fresh fruits and vegetables, even harder to explain how eating that Big Mac is liable to be the only thing remotely resembling pleasure that occurs during the course of someone's day, therefore making it exponentially more difficult to substitute a bag of carrot sticks and a rice cake, even assuming that all the various network of interdependent resources are in place to make that choice just as present and totally hers alone to make, in every other way as it is for the rich thin girl.
Nailing down the standard of beauty dial on a setting that is in the minds and psyches of many people in the Majority World, one associated with horrors like disease and famine is also not something that someone can just get off the plane and understand. Americans themselves don't really understand it, as most of those folks soon find out when they DO ask.
Even more twisted is how that poor warped notion of what constitutes feminine pulchritude becomes itself a factor in increased obesity: The "I am never going to look like Paris Hilton, therefore my prospects for just about any and everything I want in life are screwed so I might as well sit here and eat a ****ing whole pizza" syndrome.
And the undeniable-as-it-is-illogical fact that her reasoning cannot be said to be wholly without some basis in reality. As long as it remains the standard of beauty, girls who are tall, and thin, and blonde, are more likely to get the job, the promotion, the place in the educational institution, and yes, the dates.
And yes, it all has its unwholesome roots in both colonialism and the objectification of women, their no-count mama Greed, and about all we can do is hope to slay the undead and hydraform tentacles of those demons, and send the Bad Seed grandbaby of making life about twelve million times more complicated than it needs to be back to hell with its antecedents.
And to that end, may God bless Mo'Nique!