If you have a total of 5-10 items on the full menu, your food is likely fresh made.
If its a giant menu with all kinds of styles, laminated, well, it's not a kitchen back there but a conveyor belt.
If there are less items I thought that it would make it easier to standardize and ship them in, while a larger menu might require more actual cooking.
Same can be seen in high-quality fashion. A new collection every season, comprised of a few well crafted items.
And don't get me wrong, I have no qualms with fast food. I find it just interesting how few have bothered to look behind the curtain given all the cooking shows, books, etc. Bourdain's Kitchen Confidential came out ages ago.