Various scientific papers and professional references indicate that a small amount of solid fat, such as lard, shortening, or butter, enhances bread volume. The gain is at least 10%. The amount of fat usually recommended is 3% of flour. Sometimes a little more is recommended, especially for whole grain flour.
No scientific or professional source that I could find says that oil will work for the purpose of enhancing rise. In fact, melting solid fat before incorporation into the dough will diminish the effect of increasing volume. However, Laurel Robertson thinks larger amounts of oil enhance rise.
I’m not sure if the above technique is applicable to pizza. However, since I use whole wheat, rise is always an issue. My experiments with solid fat are incomplete. So far, it seems to work; but I miss the flavor of olive oil.
Has anyone else tried this technique?