UPDATE: Thanks everyone for the answers. I ended up breaking the fast, based on your recommendations and how I was feeling: I was feeling a little sick before doing it, now I feel better. Also, I believe I exaggerated the low fat percentage I had. As I said, I based on pictures detailing how different percentages look like, and depending on which one I look at, I get different results. I believe I’m at 10-15%. I’m safe, I’ll continue with a ketogenic diet for some days before going back to my normal eating patterns. Again, thanks for the answers!
Recently I hit a total of 80 hours of fasting (my personal record). I had to stop because I believed I needed food, but actually I had some bad symptoms because of elevated salt intake. I didn’t eat a lot, and just fat and protein (and some vegetables) in order to stay in ketosis. Since then I’ve been fasting again (36 hours right now) but I’ve experienced some negative symptoms. I’m feeling really cold various times in the day, and weak and tired, with some blurry vision other times, though I noticed that by ingesting a lot of water I get better. The thing is, I started my fast with less than 10% of body fat. I’ve keep my daily routine the same as before (I’ve been training strength very intensively, walking a lot, doing cold showers daily, some cardio, etc) and trained as I said, in order to, among other reasons, keep my muscle mass, which, looking at myself in the mirror, seems intact. But I noticed I already look thinner, specially in my lower back. Probably because of fat loss (my abs are even more visible now than before) but also water and glycogen.
CLARIFICATION: the body fat percentage I used to have before starting the long fast was normal for me, it was just the natural percentage for my body. Right now I have very good amount of muscle, but still visible abs and around 10% of body fat (based on what I’ve seen that percentage looks on males). I was eating enough (a lot of people actually get surprised by how much I normally eat) because I was building muscle, and didn’t have any symptoms of excessively low body fat. Its just my genetics I believe, I actually was in a hypercaloric state.
I know that we are prepared to water fast for really long periods of time, but I’m wondering if in my case I’m hitting a max before starting to have negative outcomes, or is all just some secondary effects and I should just drink more water and don’t worry too much about it. I’m fasting because of its health benefits.
Yes now is the time to break. There are benefits to fasting, but too much will stress out the body and cancel those out. Your body is indeed technically always prepared to water fast for a long time, but that doesn’t mean it’ll be smooth– you’ll survive but it generally isn’t pleasant unless you’re used to it.