Whoa! Double Down! What does it mean?

The Double Down is a controversial new "sandwich" that KFC are bringing to New Zealand next month. The new "sandwich" has bacon, cheese, and a "secret sauce" in between two Original Recipe fillets (no bread - great for those with the likes of coeliac disease) and it's a terrible nutritional choice for anyone, and those most likely to eat it are already at risk from obesity and unhealthy diet habits. The "sandwich" contains 32g of fat and 1380mg of sodium, and at 540 calories, would take up about a third of the average person's calorie intake per day, without providing essential nutrients.