Again, what defines a poor country? Singapore, for one, may be a technologically and economically advanced nation, but it's not short of poor people. The same goes for many other countries.
People are skinny for various reasons, one of them being bulimia. Most bulimics want to eat. They don't want to starve - that's why they eat and then throw up. I'd love to be able to eat as much as I want and not put on weight - but the truth is I can't. And that's why I have to resort to other means to lose weight while being able to eat.