I have been thinking and trying to analyze what is really causing the high cost of food in Nigeria, I came to realize that monopoly is the major factors, Nigeria government are the enablers. How can one person be the sole major distributor, government should welcome competition in the business sector, every business person should be allowed to produce.
As per your statement, they can easily manage to manipulate the number of foods they can hoard as much as they want, we know how does the government have power for the economy reason why some of community or even country fails to manage properly and the people will suffer with this greediness. You cannot reduce this if the government doesn't take any action else you will do something like make your own plantation of the resources you need its more cheaper than buying those into malls and market.
Often we get to see a viral video in which a farmer and a corporate sits next to each other and sell vegetables. The corporate quotes a higher price whereas the farmer sells at a lower price. At some point the corporate guy buys everything from the farmer at the quoted price and he further double the price and sell the vegetables. This is what happening in reality, the producer doesn't get anything, the profit is eaten by the corporate. We need to be self reliant to cultivate what is necessary, only then it is possible to fulfill our food needs in the future. Because, the involvement of corporate into food industry isn't big, soon this will go high and everyone needs to be under their control.