Shakes, I think you're mistaken. Back in 2001 when the cell phone ban was being worked out in New York, eating while driving was the other thing it addressed. That portion of the New York law was removed before the legislation passed.
Texas and other states have talked about making laws to ban eating while driving, but as far as I know, none of those talks have made it to law yet.
Of course, decisions like this are (and should be) made at the state level. Hanzacara makes a common mistake, I think, in assuming that there is a single US wide law defining video display. Likewise, anyone who asserts that it is flat out illegal to eat while driving in the US is also in danger to overstating things.
It may be the law where you live, or in some cities, but it's not federal, and this website extends slightly further then your home neighborhood.
Of course, my post only applies to the US. Hanzacara is referring to a California law. CA is big, but despite popular opinion, it's not the whole world.