Sudanese women moving to shed pounds as ideal body image changes

This is a billboard from Khartoum, Sudan advertising a weight loss center and gym. There are more and more of them popping up around the city, in a country and society which traditionally valued a woman's plumpness.

Welcome to a changed Khartoum. At least in terms of what women want to look like, and how much they want to weigh. 

Thin is in, and that's a complete departure from tradition.

So, what happened and why are Sudanese women changing?

Listen here, in a report for PRI's The World, which was also broadcast on BBC.