Preheat oven to 350 degrees. In a large bowl place the white cake mix (reserving 1/4 cup for later), water, oil and egg whites. Mix on low for 30 seconds, mix on medium for 2 minutes with a hand mixer.
Toss blueberries with the remaining 1/4 cup of cake mix. Fold in blueberries into batter. Pour batter into a greased 13x9 inch cake pan. Bake 25-30 minutes until a toothpick inserted in the center comes out clean. Let cool on a wired rack for at least 2 hours.
With a rounded wooden spoon handle, poke holes all over the cake about 1 inch apart. Mix pudding with milk per the directions on the back of the box and immediately pour over the cake. Using a spatula, gently smooth pudding over cake trying to press it into the holes. Cover and place in the fridge for one hour.
Top with whipped topping and serve.
Lemon Blueberry Poke Cake Recipe found on https://thissillygirlskitchen.com/lemon-blueberry-poke-cake/ *All nutritional information is approximate and may not be 100% accurate. Please consult a nutritionist for more specific information.