I do think there should be a differential between fast food, and junk food. Baked beans on toast with a poached egg on top is fast food. McDiddles is junk food. Chicken soup with crudites is fast food, chicken nuggets are junk food, (Unless you make them yourself). A sparkling fresh salad with fresh crunchy bread is fast food, a dressing soaked salad, with a sad reflection of attempted grandeur, but showing its age is junk food.
I would love it if fast food lost its title to junk food. It was neither earned nor deserved. Now I shall eat some butter, pate , fresh toms, lettuce and beet stuffed determinedly into a french loaf. A gerkin or two never goes amiss and the cheese is so ubiquitous it doesn't rate a mention. Sliced hard cooked eggs get a bit of mention I suppose, and generous amounts of avocado if you have one to hand. Fast food donchaknow.
One the other hand I could buy a bread full of processed stuff. Junk food. I do hope you get my idea. I am not trying to be mean at all.