The 1lb a day is a good rule of thumb, but it will not always hold. There will be times when it feels like your body is just stuck. I myself experienced what i called a "plateau" in weight loss that lasted for close to 6 days. It was frustrating because you become accustomed to the rapid loss, and watching your body change from day to day. But remember, no matter what your body is healing itself and it is changing, whether the scale shows it or not. So if your progress does slow down dont be disheartened! I found it helpful to remind myself why i was fasting in the first place, not for weight loss alone, but for a cleansing of body and mind, and a fresh start. Focusing on the superficial can be a slippery slope and make fast more difficult.