I would suggest looking at the way of eating set out in the How Not to Die book by Dr Michael Greger. It is about "the foods scientifically proven to prevent and reverse disease" and contains almost 200 pages of Notes citing the scientific research he draws on at the back of the book. So, it's not some flaky, faddy diet idea.
He advocates eating a "Daily Dozen" to incorporate the food he considers essential to the optimal diet. This blows the current 5 a day out of the water, and means that you are so full and satisfied from all the healthy stuff you have to eat that you have neither room nor inclination for processed junk!
There's a lot of info about it online, and talks by Michael Greger on You Tube. He donates all profits to charity - and interestingly for GransNetters was inspired to go into medicine by the remarkable recovery of his grandmother who had been sent home to die by conventional doctors, in her sixties. She sought treatment from Nathan Pritikin, an early lifestyle medicine pioneer, and lived to be 96.