Quarter Pounder Big Mac. A Quarter Pounder has ingredients found on nearly every burger at McDonald's: ketchup, mustard, cheese, pickles, and onions. For me the fast food burger hierarchy goes Quarter Pounders are thick and juicy and I like the bite and crunch of the onions they use.
No a big mac is something different. Meal, Quarter Pounder, Large Fries, Large Coke. Also, "quarter Pounder" refers to the meats pre cooked weight.
Including Big Mac, McNuggets, McRib, Dollar Menu, McCafé Cinnamon Cookie Latte, Donut Sticks and more!
Get one of each, and you will see the difference.
By comparison, the Big Mac is a mediocre burger. But apples to apples, McDonald's Quarter Pounder. It loses juices and mass during the cooking process.