SlimFast Snack Bag Sour Cream Pretzel are a quick and easy snack for on the go or while at home. Each bag contains 99 calories and are part of the SlimFast 3.2.1 plan to help lose weight and keep it off. The Slim Fast Sour Cream Pretzel Snack Bag are a tasty snack that can contribute to weight loss and used as part of the Slim Fast 3. 2.1 Plan. The sour cream pretzels are a wheat and potato pretzel snack which are oven-baked with sour cream and chive flavour, ideal for when you\'re on the go or at home.