In US English this means the speaker consumed four cans of "chip dip" - which is a mind boggling amount to consume in one sitting. Chip dip is a flavorful prepared sauce for eating chips (potato chips, corn chips, etc.) with. You dip the potato chip in the sauce and then eat it. The dip makes the chip more flavorful than if you ate it plain. Usually one can of dip would be more than enough for