Nutrition. One slice of pepperoni pizza contains 298 calories, according to the website FatSecret. It contains 12.1 g of fat, 5.3 g of which are saturated. It contains 29 mg of cholesterol, 683 mg of sodium and 186 mg of potassium.One slice also has 34 g of carbohydrate, 1.6 g of which is fiber, and 13.3 g of protein.se low-fat turkey pepperoni to limit calories and sodium. Regular pepperoni has 132 calories per ounce, along with 11.4 g of fat and 507 mg of sodium, according to the website CalorieKing. Turkey pepperoni has 76 calories per ounce, along with 4.3 g of fat.