There isn't much data available on the whole "unfamiliar" food thing, as we on the boards have relegated that to being extra credit (I think, that's my opinion anyways) other than avoiding ditto foods (for example, McDonald's food).
I'm of two minds about this, as one of the classic examples of unfamiiliar food would be going to an "ethnic" restaurant and ordering something unfamiliar to you in flavor. Lets say you went to a Vietnamese restaurant, and ordered a bowl of pho (a noodle soup with broth flavored with several very different ingredients). All together the effect is that the flavors are unfamiliar, which indicates that it would qualify as an unfamiliar food. But the thing about pho is that spices and broth aside, the base ingredients are just noodles, beef, and bean sprouts, all familiar foods...
So one part of me thinks that your example, eating cornbread WITH soup would definately qualify as an unfamiliar food as there is enough unfamiliar-ness there to qualify.
But then the other part of me thinks that maybe it isn't unfamiliar enough...
So I don't know. Frankly I think its admirable that you're trying to move away from familiar foods, but I'd focus mostly on avoiding processed ditto foods, like prepackaged junk food, fast food, canned soups, etc... If you already do that and want to really be the A+++ SLD student, then I think what you may want to do is really go the distance and try eating the unfamiliar flavors all by themselves, then have the cornbread (or vice versa) so that you don't undo the benfits of the unfamiliar soup.
But then another part of me says that you're probably doing good no matter what the theory says, so just stick with what YOU think works for YOU. That, I think, is really one fo the SLD principles, that the base method should be followed by everyone, but that the other stuff really depends on the person. Which is why some of us do low carb, some of us do noseclipping, some of us do vegan, some of us avoid wheat, some of us do crazy spicing, some of us don't need to do anything other than take our oil, and some of us need to be on really strict diet and exercise plans on top of SLD to be effective...
So my suggestion is that you just play around and do what YOU think works, because that's the only way you'll tell if it really will work!