Why can't people feed themselves?

When I started I saw a world divided into two parts: a minority of nations that had "taken off" through their agricultural and industrial revolutions to reach a level of industrial revolutions to reach a level of unparalleled material abundance and a majority that remained behind in primitive, traditional, undeveloped state. 


...when looking for the historical roots of the predicament, I learned that my picture of these two separate worlds was quite false. My "two separate worlds" were really just different sides of the same coin. One side was on top largely because the other side was on the bottom. Could this be true? How were these separate worlds related?


Colonialism appeared to me to be the link. Colonialism destroyed the cultural patterns of production and exchange by which traditional societies in "underdeveloped" countries previously had met the needs of the people. (Lappe and Collins 1978, 75)