ummm, that's kind of an interesting take on nutrition. Mass, keep in mind the way in which each person's body works is unique in many respects, but physiologically speaking its hard to determine what will happen to the deposit of bad shit in a person's body. I mean realistically speaking, you need to examine not just your diet, but the way in which your body works, and how you train to determine how to optimize your plan. If you are worried about a gut deposit and you want to spread mass you need to consider what "clean" foods you do consume, and how they effect you. The Wendy's and McD's stuff can work in a pinch, but regardless of what is put in their nutritional profile there are other factors to consider: Glycemic content, What kinds of fat are present in the food. Keep in mind also the foods are prepped in a manner which IS inconsistent, amounts of cooking aids (butters, oils etc. change)
I would be a liar if I said I didn't have a yearning for fast food, but it helps to consider what is it you enjoy at a fast food joint, and then create a healthy alternative. Just about any item can be created at home in a manner that helps to optimize the "cleanness" of the food item, and conform to dietary needs. If you control your diet and what you take in, you can prevent the gut sooo easily and mass up to a level that is controlled and easy to cut later.
At least thats my take