My almost certainly incorrect chronology of events, cobbled together from pop science headlines I've read:

1) Free radicals are bad because they cause oxydation (oxydization?) and this is bad for our cells? 2) Thus, anti-oxidants are good, because they prevent this process 3) People recommended more dietary anti-oxidants 4) It turns out that ingesting anti-oxidants doesn't actually produce the antioxidants necessary to combat free radicals, the same way eating dietary fat doesn't create human fat. Dietary sources of anti-oxidants largely are not absorbed and are useless. 5) Instead, we should look for foods that stimulate production of anti-oxidants in... the liver? the spleen? Wherever those are made in your body? But no one knows which foods are good for that?