xeroid,
Only a tiny part of the cost of food is the cost of energy used to produce it, energy calories are very cheap and food calories are fairly cheap. Most of the cost of food is the processing, packaging and marketing costs. A bushel or wheat or maize makes a lot of bread or cornflakes.

I don't sit in a field eating corn, I eat bread and cornflakes in a city, so it's the embedded energy in the final food on my plate that is important to my way of life - unaffordable energy means unaffordable food, no matter how low cost one particular input is.