Corn oil is very inflammatory and has fallen into disuse because of that.

In the recent past, "vegetable oil" was mostly trans fats, unless it said clearly on the label where is was from. Wesson oil and Crisco were the dreaded transfats for many years.

Now it may be, sunflower, or safflower, both omega-6's.
Canola has some Omega-3's so is preferable if you want to
control inflammation. Soybeans are a vegetable and qualify as well and are mostly omega-6.

There are no carbs in Corn oil, but that is not the reason to not use it. Corn oil is just very inflammatory.

Since we eat so much omega-6 in our food, you need to limit it and add omega-3 like flax.

Here is a chart showing what is in each oil.
http://curezone.com/foods/fatspercent.asp

I explain Omega-3 and Omega-6 in my EFA thread:
http://neurotalk.psychcentral.com/showthread.php?t=6092

When you see the words "good fats" in articles, they refer to Olive oil and Omega-3s mostly. (some Omega-6 are okay, but too much is inflammatory).