Summary of the summary in that link -- Michael Pollan points out in his book "Omnivore's Dilemma" that there's an increasing amount of corn in our diet. He then goes to show that corn is inefficiently used and subsidized despite the large profits that corn growers reap. He then starts taking potshots at a food industry which he perceives as based on energy loss.
I think that "cornie" is an appropriate term for one whose opinions fall on a similar line.
It's an interesting observation taken to an extreme conclusion. It appears from the cornie's comments to overlook several important points like the sources of energy production, assumes a few about economics, and uses a limited understanding of nutrition to claim doom upon us all.
Statements from the cornie on nutrition and energy.