It’s usually recommended to refeed with half the fasting time, so in your case you would actually need to refeed for 7 days. Of course that is just a recommendation, there are a lot of people who sometimes break their fast by going to an all you can eat restaurant, but you should never do that. The refeeding is probably more important than the fast itself. If you have an upcoming vacation I would recommend to do rolling 72s so fast for 3 days, refeed with one meal, fast again for 3 days till your vacation. That would keep you in the safe side and is probably better than risking getting sick on vacation because you can’t digest the food. But that is only a recommendation of course, if you plan on doing a fast then I wish you the best of luck, you can do it 🍀