Well, I took you " round about" to say....that's exactly what happens to the insides of us. We can eat so many things but the truth is, only certain things benefit our inward biological "appearance" of looking good. And that "looking good" is what you want to hear the doctor say, "everything looks good"! To be our biological best, including moods, attitudes, cognitive performance, as well as all the basics, we better think before we bite.
I came across a great little article (and a good source of information) to really underline the importance of understanding our "machinery" and how it's our own personal responsibility to maintain the machine to the best of our ability....and, that includes finding a level of enjoyment and pleasure that is equally satisfying. Remember, molecules are what stuff is made of and there are rules as to how you put things together to have them be what they were intended to be. :)