Al Eisner wrote:

But in any case, In-N-Out doesn't satisfy the original criteria, since
it's not a fast food place. Typical time delay is similar to that of
good non-chain burger places (unless one goes at very-off hours).

You and I have different definitions of fast food. In-N-out,
Val's, Nation's, all count as fast food. Anyplace that you pay first,
that produces your food within 15 minutes, and from which you normally
leave right after eating is fast food.

Chain vs. non-chain doesn't enter into the definition for me.

Steve