Read the GoDiet book. It is theone that explains how yogurt and butter milk have less carbs then stated because of the bacteria. I havn't read that book, just the summery given in 500 Low-Carb Recipes. I havn't tried buttermilk. I do eat 1/2 cup of yogurt everyday and still do well at losing. I also count the full amount of carbs listed on the container however, instead of reducing the number just in case.