If you eat out, here's how a few popular burgers compare: 1  McDonalds Hamburger: 240 calories, 8 grams fat, 3 grams saturated fat. 2  Burger King Hamburger: 220 calories, 8 grams fat, 3 grams saturated fat. 3  In-N-Out Burger Hamburger with Onion: 390 calories, 19 grams fat, 5 grams of saturated fat.