I was a "foodie" for years. I ate whatever I wanted but it was mostly very SAD-healthy. I ate all sorts of grains from various sources, lots of beans, and used canola oil, but that was about the worst of it. I didn't eat much in the way of processed foods for years, no HFCS, little soy, and I did most of my own baking when it came to dessert stuff and I didn't eat bread at home often.
Before that? Late teenage-early adulthood years consisting of tons of boxed rice mixes, Hamburger Helper, baloney sandwiches, breaded chicken tenders, Little Debbies... the usual icky. Still somewhat SAD-healthy but not so gourmet and much more processed.
As far as influences? Mass media, USDA recommendations, the usual CW. (Why I believed that stuff for so long on the subject of diet, I have no idea. I saw how stupid the CW was when it came to my pet sciences, so I don't understand how it took me so long to realize that it was silly to listen to magazines about diet that call the Higgs the "God Particle," for example).
I got on the Paleo bandwagon pretty easily. I was used to forgoing most of the processed/convenience/junk foods, so it was a lot easier for me than if I'd started in a worse place, I think. I took the last step after I took some prescription medications and developed an ulcer and really bad digestive symptoms that pointed to gluten intolerance.