Can white flour be substituted for whole wheat flour (or vice versa) in a 1:1 ratio in recipes?

I had the same question and found this at the BHG site: "Substituting whole wheat flour for white flour takes a little experimentation, but you will almost always be successful if you use ¾ cup of whole wheat flour to replace 1 cup of all-purpose flour. When making cookies with whole wheat flour, reduce the butter or shortening by 20 percent. When making cakes with whole wheat flour, add another tablespoon or two of liquid. When altering a white bread recipe to become whole wheat bread, you may need another ¼ cup or so of liquid." Also that white whole wheat flour, which is "milled from albino grains of wheat—behaves almost exactly like white flour, but provides all of the whole grain goodness of wheat flour." (www.bhg.com/advice/food/baking/can-i-substitute-whole-wheat-flour-for-all-purpose-flour-when-baking/)

The 1:1 substitution doesn't work in either direction. Whole wheat is a significantly larger, more complex particle than white flour. It also has a significantly higher protein percentage, both of which cause it to take up liquids differently than white flour. If you want to sub white for whole wheat, plan to use more white flour. Start with 10% more, than add additional if need be. If subbing whole wheat for white, plan to use less. Start with maybe 25% less, then add more if you need to.

It depends on the recipe, but probably no. It's safer to substitute whole wheat flour for only half of the flour in the recipe.