Air density at lower altitudes is higher, and thus provides more resistance to objects moving through it. Is this higher density enough to practically impact the fuel efficiency of an aircraft flying at low altitudes?

For example, if a B777 enters a holding pattern for 60 minutes just outside an airport at maybe 5,000', is it going to burn significantly more fuel than if it had (for whatever reason) entered the same holding pattern in the middle of cruising at 40,000'?