What it means is white sugar, white flour, white pasta, white rice, white bread are all out of your diet. Eat brown sugar or honey, wheat flour, wheat pasta, brown rice, wheat bread instead. It doesn't literally mean anything white: yogurt, milk, etc. are still OK. It is just about getting back to the more natural form of foods, less processed and without the nutrients taken out. The result is a higher fiber and vitamin rich diet that leads to your body being healthier and your bowels being clean.