Why a Big Mac Costs Less than a Salad - Economix Blog

The numbers here are interesting, but almost entirely irrelevant to the question being asked. Most of the cost of a Big Mac -- or a salad -- is not the cost of the ingredients; rather, it's the cost of handling and preparing them.

This is where the Big Mac has a huge advantage: You can freeze hamburgers, and upon thawing they are just about as edible as they were to begin with (which isn't saying much, but that's a different issue). You can't freeze a salad and have it come out very edible -- so salads require more and smaller shipments.

Add to that the care needed in preparation -- you don't need to worry about keeping a hamburger sterile, since it's going to be cooked long enough to kill any bacteria -- and it's not at all surprising that salads are more expensive to produce than hamburgers.