How did forcing Africans to grow cash crops during the age of new imperialism lead to famine during the twentieth century?

pretty self explanatory here. Cash crops aren't meant for sustenance, they're made to make money. As imperialist powers finally let go of their colonies, the battered and torn countries (in most cases) that were left behind were left with no economic resources, as they all went to the colonizers. This left the developing country no choice but to give up and start having having tons of sex with everyone. The cash crops grown boners boners boners the last remnants of Imperialism. A wise man once said "GILF shemalle, get drunk now"