Use freshly pressed juice (not bottled or canned – you will need a juicer) if you are doing the juice fast, and make sure it is mostly vegetables, with plenty of greens. Fruit juice may be tastier, but contains a lot of sugar. You might also want to add filtered water to dilute your juice. Experts I have read suggest that a juice fast is superior to a water fast because the juice binds to the toxins and helps carry them out of the body, in addition to providing some nourishment. With a water fast, sometimes the toxins can get reabsorbed by your tissues before they have a chance to get excreted.
If you’re doing either of these cleanses, I find its best if you have the luxury of staying home while cleansing. You may feel weak, headache-y, cold, and/or tired during the fast. Take it easy. If you normally run and want to exercise, consider walking instead. Unless you are doing this under doctor’s orders, don’t stay on it more than 1-3 days. And be cautious of how you come off the fast. Don’t go out and have a humongous meal as soon as it’s over. Ease back to normal eating gradually, over a few days. If you’ve done the Master Cleanse, break your fast with fresh fruit/vegetable juice or broth. Next maybe have a light salad. After that add in some cooked vegetables, and add meat back into your diet (if you eat meat) last.
As always, check with your health care provider before embarking on this or any other therapy – especially if you have health challenges. (The lawyer in me had to add that caveat :))