I definitely plan my extended fasts. Not just the fast itself but also my refeed. Timing is important (maybe more so for women than men) but I make sure I don’t have anything strenuous or requires too much brain power toward the end.
After 48 hours you’ve pretty much exhausted your electrolytes so you need to supplement and stay hydrated. And a safe refeed from an extended fast is different than what you may have done coming off a 72.
Also, if you feel unwell at any point, don’t be a hero. Break your fast with bone broth, even if it’s 2am.
Be prepared to gain back at least half of what you lose. I use these extended fasts to address inflammation and renew immune cells, I haven’t found them all that beneficial for weight loss. YMMV. Good luck.