Corn is off the Paleo menu, because it is a grain. It is high in carbohydrates, low in fat, and the fat it does contain is mostly polyunsaturated fats (PUFAs).
Paleo and PUFAs
Those of us living a Paleo lifestyle try to limit our intake of PUFAs because they tend to be highly inflammatory and damaging to our bodies. The invention of industrialized oils (such as corn) have introduced a record high level of PUFAs into our diets.
Omega-3 vs. Omega-6
Corn oil is especially high in omega-6 fatty acids, a type of PUFA that is highly inflammatory. Omega-3 PUFAs are anti-inflammatory and we should be eating at least as much omega-3 as omega-6, if not more. Thanks to the cheap, hydrogenated oils now available (and conventional wisdom’s conviction that butter is unhealthy), most Americans are consuming far more omega-6s than omega-3s.
Mark Sisson included corn oil is his guide to oils.