Preheat the oven to 325°F and grease a 10-cup bundt pan (I used this one) and set aside. In a large bowl or stand mixer fitted with a whisk attachment, mix together the cake mix, pudding, and egg whites.
Beat in the vegetable oil until combined.
Gently mix in the soda on low speed until smooth.
Divide the batter into three separate bowls and color one them with red food coloring and one with blue and leave one plain.
Use small or medium cookie scoops or tablespoons or portion out the dough in the pan, alternating to try to put the different colors next to each other.
Bake for 45 to 50 minutes or until a cake tester comes clean from the thick part of the cake.
Remove from the oven and allow the cake to cool in the pan for 20 minutes before flipping onto a cooling rack or plate to cool completely, about another 40 minutes before icing.
To make the icing, simply whisk together the sugar and soda until the desired consistency is reached. Then pour over the top of the cooled cake and top with sprinkles.