Car queue at the McDonalds drive-through in Anaheim, Calfornina.

McDonald's menu has become so unwieldy that even the chain's U.S. president doesn't know how many items it contains.

On a recent investor call, Michael Dean Andres noted McDonald's has added more than 100 stock-keeping units (SKUs) during the past decade— making it more difficult both for consumers to order and for employees behind the counter to fill orders quickly.