I completely agree with your advice of following a diet based on the principles of natural hygiene, and that you are what you eat etc.
However I personally find it quite hard to eat well, I know it's a poor excuse but the bad stuff is just so accessible, cheap and indeed designed, marketed and promoted to tempt us. i.e though it would be a good idea to prepare a healthy lunch each day, it is so much easier to grab a takeaway from somewhere. I know that scientific research has shown that high fat, high Sugar foods trigger the same pleasure receptors as do illicit drugs which perhaps explains the prevalence of obesity etc and why it is so hard to change.
That said, I am trying, but I guess old habits die hard and as long as I improve my diet overall don't worry too much about the odd slip up. Just does seem odd to me that I should want to eat junk in the first place. Must be a screw loose somewhere!