GGB One leaking line is a fix; several is a structure. The published GCC bands are the honest yardstick: food cost at or under 32%, labour at or under 30%, prime cost at or under 62% of revenue. If two or more lines sit above their ceilings — or if you cannot say where they sit — the problem is structural, and structural problems do not fix themselves while everyone is busy with service.
From What Does a Restaurant Turnaround Consultant Actually Do? — the full reading, with the method behind this answer.