three days or a week? Worth it to fast for longer in terms of health benefits?

Hi! I’ve been intermittent fasting for a long time now. Recently I changed my eating schedule and started a 4 hours eating window normally. With some times (in particular every two weeks) a 24/40 hours fast, the last being my max. This week I had the opportunity of experimenting and going for a longer fast, my goal is at least 72 hours (I’m around the hour 60 and feeling great) but I’d be able to prolonger it to a full week. I wanted to see some opinions on whether is worthy for me to extend the fasting state even longer than the three days. I do fasting for the health and probable longevity benefits, but I have very low fat. So much that my body naturally allows me to have six pack abs, without counting calories or paying a lot of attention to try to “stay lean”. I actually eat a lot and try to eats as much as possible, as I’m trying to build muscle. I still train during the fast to avoid muscle loss, but I suppose that probably after three days my body will have to get energy from somewhere else. I’m not very worried about it though, since muscle mass is difficult to build but easy to recover. Though I guess I will not be recovered for my next workouts. I’m not sure how much fat can be used from my body to continue fasting without having any negative consequences.

So: is it worth it to continue fasting in my condition? I’m thinking of maybe eating fat and protein (to maintain ketosis) after I complete the 72 hours and then start a new fast. Or maybe just fast the whole week, but I’m not sure if I’m actually maximizing the health benefits that way.

TLDR: I have very low body fat and I’m worrying if it’s worth it in terms of health benefits to fast a whole week or just end the fasting state after three days, and maybe start a new fast of similar duration.