Dinner Guest: In search of real food

I have written a few articles about substitutions, explaining how to take the sodium from astronomical numbers to more manageable and healthier levels. However, there are some instances, where I think substitutions are, basically, the devil. My wife and I talk about food substitutions all the time. She seems to be quite concerned about my health, even more so than I am.
She said something to me and I believe it to be true: “Never substitute non-food for real food.”
For example, one s