Fasting is not intended to solve or resolve world hunger. Its not even about hunger. One of the fundamental concepts in Islam is that it is a return to fitrah, i.e. a return to our natural constitution, to what we are intended to be. The purpose of fasting in Ramadan is to sort of remind ourselves of the instincts that rule our lives, hence the self restraint and discipline, in the face of hunger, thirst, sexual celibacy and controlled aggression during Ramadan. And since its not intended as a punishment, it has a very finite time limit of sun-up to sun-down. Its about getting control over oneself, of devoting oneself to focusing inward and towards God. It has nothing to do with poverty or starvation of millions. If you fast in Ramadan, you should do it for yourself and ONLY for yourself, not for anyone else or as a social obligation or community feeling.