about the food:
the food itself is GENERALLY real food, but not always in great, edible condition.
Bread is usually stale, food is either under or over cooked, recently cooked but frozen afterward or something similar, and colors are touched up in post-production and other tricks.
Especially regarding fast-food - the finesse in crafting the most beautiful product will not be found inside the restaurant. Just stacking ingredients in that way, and getting all items perfectly cooked, seared, and otherwise finished to absolute perfection... never gonna happen.
You can see "real" photos from major restaurants, where the only tricks are typical post-production photography and different approaches to "studio" lighting or other lighting work. Those you can often find the final meal looks remarkably close to the glamour shots, because for high-dollar food, they do take that time to meticulously design the final plate appearance. They might do some additional food tricks, just because of the same reason for post-production work - it's difficult to get the camera to see what the eyes see (which adds in brain filtering/"post-processing" - there's a lot of psychology/neurology to vision, believe it or not).
Facebook
Twitter