I scream. You scream. Here are six of the most fattening ice creams to make you scream. Newsweek did the leg work, so all your leg work won't go to waste by over indulging in these fattening flavors. I know ice cream is fattening to begin with, but add in peanut butter, nuts, pretzels and fudgy bits and the caloric content goes sky high in some of our favorite flavors.