It seems to me that you are saying that you currently eat only once every 48 hours. If so, you are already doing short fasts. Some people do recommend that you prepare for a long fast by eating clean, juice fasting, or doing short fasts. That's not completely necessary, though if you can only Water Fast on vacation, which is so for some people, those things can extend the time you have for healing by doing them while you are still working, since they are healing in their own right. You can extend it a little more by starting your fast a day or so before your vacation starts. Fasting during a vacation is really ideal because you should be resting or at least taking it easy when you fast.

JJ,

I do not know how many fasts have you done before. 20 days is a good goal, but if you can do following things you can go ahead and start.

1. Drink water as per thirst. Drink nothing but water, warm or room temperature
2. Rest plenty
3. No strenuous work and no stressful situations
4. Stay warm. Your body heals better when warm

I do not understand the last line, you are eating every 48 hours? If I understand you correctly you want to continue eating every 48 hours. I think you can eat every 48 hours but it would not be considered 20 day water only fast.

Good wishes.
Archus