Place the flour, baking powder, baking soda, xanthan gum, gelatin and salt in a plastic bag and shake very well. This can also be done in a bowl and mixed with a whisk. In a medium bowl, beat egg whites for 2 minutes then add the yogurt, oil and water and mix for 1- 2 minutes. Add the dry ingredients and mix for 3 minutes.
Spay a loaf pan with cooking spray and dust with some flour. With oiled or wet hands, remove the sticky dough from the mixing bowl and place in loaf. Smooth the surface with wet or oiled hands. The top can be brushed with some butter if desired. Bake for 30 minutes at 350°F, then cover loosely with foil and bake an additional 1 ½ hours. Remove from pan let cool thoroughly, then slice and keep in plastic bag to keep fresh for days, or the freezer for longer. Makes 1 loaf (13 slices).
Variations: Cinnamon Raisin Bread: Add 1 cup raisins, 1 Tb cinnamon, 1/3 cup sugar and reduce baking time to 40 minutes. Orange Bread: Add 2 tsp vanilla , 1/3 cup sugar and the zest of 2 oranges. Savory Olive Bread: Add 1 cup slices green olives, 1 tsp thyme and used olive oil.