And a Diet Coke

Four magic words which completely completely invalidate your prior sentence, protecting you from calories, thus preventing you from feeling bad about the massive amount of fat and carbohydrates you're about to consume. Used after ordering food, especially fast food. This sentence is used much the same way as "No homo" and "But I'm not a racist" are used.

Cashier: "Welcome to McDonald's, how may I take your order?"
350 lbs: "Yes, I'd like a Big Mac, extra bacon, extra cheese, an order of twenty Chicken McNuggets with BBQ sauce, A McRib, A large order of fries, Two Chocolate chip cookies, and a McFlurrie with M&M's. And a Diet Coke. I have to watch my Blood sugar after all."