Yes this is perfectly safe. Usually the general consensus in well know/read DF books is time dry fasting Is how long you need to replenish afterwards.E.g 36 DF followed by 36hr rehydration and food
If you were to follow this twice a week that’s 6 out of the 7 days in the week.
You will find dry fasting much easier than water fasting and by flying past 1.5 days
Enjoy