I adhere to an extreme and freaky diet that would never be approved of by modern American society. It is under the arcane and occult name of "sensible eating". No "principle" or "path" or "way", just not too much of a variety of things. The standard American diet is a mess, I'll agree, but the answer to this diet of utter excess and dysbalance (it's not "out of balance", it has a bad balance) is not an extreme in any "opposite" direction. Why does "low carb" look like it works? Because the standard diet has a severe excess of refined carbohydrates (both sugars and starch) and a severe shortage of the various "buffer" components in plant foods (aka everything that isn't sugars and starch). Bread isn't the demon, it's eating a half loaf of white bread at a sitting (or an equivalent in potato chips, white rice, etc.) The whole "paleo" schtick is just another excess reactionary diet.
Yes, some food could be legitimately called "junk food", just like sitcoms could be called "junk TV" (eclairs or potato chips are never actually healthy, no matter how nicely made, merely somewhat less unhealthy), so DON'T LET IT BE A BIG PART OF YOUR DIET! Puritanism is vile, including dietary puritanism.
Unless someone is only willing to watch documentaries and read "uplifting" or "enlightening" books, only indulge in "edifying" conversation (no jokes), etc., why be puritanical and fanatic about food?
Finally, regarding the Wendy's hamburger: It IS different from the one I make at home. It obviously has more grease/fat and a lot more salt. I can taste the salt difference and see, feel, and taste the grease difference. I still eat Wendy's hamburgers, just not that often.