Juicing For Detoxes

Hi, Just a question about juicing when doing Schulze's Liver/Kidney detoxes. The Bowel Detox doesn't require a specific diet.. in the Bowel Detox book he says its better to eat cleaner, but not essential. Why is it though that its specific that you have to fast on the Liver and Kidney Detoxes then?

The problem you see, I am more underweight then overweight, and unless I eat a lot of calories in a day, I can feel physically weak and feel like doing nothing. Now i've had a quick add up in my head.. if i have 8-10 ounces of juice, every hour for 8 hours, each juice would probably contain around 100 calories (and thats providing its fruit juice!) so in total in a day i would only have around 800 calories. But a few of those juicers would be vegetable / green juices, and even if i added SuperFood I would probably only consume between 600-800 calories a day. There is no way i could get through many days like that.. Can anyone give me advice? Tweet