Velcerick, flour and baking powder are not interchangeable. Baking powder is a leavening agent so if you leave it out your bread will be very heavy!

markdallas, I like to use half almond flour and half flax meal, or sometimes even 1/3 of each plus 1/3 whey protein powder. I have a small tub of the latter mixed up in my cupboard ready for baking! All I have to add is baking powder, egg, and any other liquid or spices I decide to use.