McDonalds Hamburger: 240 calories, 8 grams fat, 3 grams saturated fat. Burger King Hamburger: 220 calories, 8 grams fat, 3 grams saturated fat. In-N-Out Burger Hamburger with Onion: 390 calories, 19 grams fat, 5 grams of saturated fat. McDonalds Big Mac: 530 calories, 27 grams fat, 10 grams saturated fat.