Well, as long as you know what you're doing, Bannor, then I'd say there's no real danger. Though seeing as your overall health seems to be precarious based on your previous posts, I guess I'll sound like a broken record to you if I tell you to be careful.
I've fasted before myself, mostly for the same reasons. There's too few hours in the day and I spent most of my Bachelor's Degree running left and right catching up with classmates I'd been paired with or just working my ass off to keep up with set deadlines. That included accidental fasting after two days of six hours of class a day, plus five hours of work. So, well, I just forgot to eat at times. Sometimes for two days straight. I ran on bad coffee and almost a crate's worth of water bottles per day. Never crashed once naturally. Only time I did was when I was goaded into trying Guru, one of the local alternatives to Red Bull.
That... was not fun. Things start to feel too slow, like you've developed a flash-speed case of ADD, and then they feel too fast. Then the head pounding kicks in, along with heart palpitations and a fair bit of cold sweat.
Yeah, no Guru for me, ever again. Which is kinda weird, seeing as I'm a *very* occasional consumer of Red Bull, and it barely affects me. It just keeps me awake and doesn't exactly tweak me the way Guru does.
Anyway. So long as you listen to yourself enough to know when to stop, and that you can recognize signs of your body wanting to crash until further notice, you'll be fine. The best pick-me-ups ever to exist are still food and sleep.