Mix whole wheat flour, all-purpose flour, yeast, sugar, and salt in a large bowl using a spoon. Pour in water and oil; mix until dough no longer sticks to the bowl. Turn dough onto a lightly floured surface and knead for 5 to 8 minutes.
Transfer dough to a greased bowl; cover bowl with a clean towel. Place bowl in the oven with the light turned on until risen, about 1 hour.