Yes, that is possible, but I think if I had begun working on a daily basis in a fast food place, perhaps beginning my career at the counter, later in the kitchen, assistant manager, manager, maybe regional manager, etc., there would be too many temptations for me not to suffer from some adverse consequences. Fast food does taste good and it's easy.
Tau is just a protein.
Adults are adults, though and are responsible without nannying to make sane choices. A big enough deal has been made about calories, fat, and nutrition that there is no excuse not to know to seek not to live on hamburgers and milkshakes alone. Even yet, beside the meager fare of more sickly ancestral times, a hamburger diet would be a comparative godsend.
I’m sure it’s possible to make less-fat, less-sugar versions of most fast food items. Baked rather than fried, and that kind of thing. Nobody’s clamoring for them or they would be offered.