I think the argument is that economics and politics are not independent of each other. They are two sides of the same coin. Whomever controls the food supply has power over the population, which means it has political power. Whomever has power over the population, has power over the food supply. Basically, economics and politics are different perspectives on power.
For example, the political structures in the West create the rules over who gets to obtain power through the economy. From the other direction, the people with economic power get to control who gets to obtain power through the political structures.