You plan is interesting and I'm glad it's working for you. I also have mine and surprisingly, after 80 days, it's already a routine, a lifestyle that is totally doable. I've heard of intermittent fasting and I know what it means, but have never tried it.
My cousin is doing something similar (or maybe not). She has 2 days per week, with 500kcal per day. It is not good in my opinion, it's damaging, but she shays it's working for her. A few years ago I was visiting her and she had her diet day, so she asked me if I want to join. I said yes, partly to avoid being rude and difficult, and partly to try it our, how strong I am.
I got through the day, but with a really heavy headache and could not even take a painkiller as who takes medication on an empty stomach? The result? 200g weight loss 😆 She said she's usually losing 0.5 to 1 kg after such a day. So no thanks, that's not for me.
My diet is simple. I am avoiding fat meals with high calories, but I have a slice of bread or two a day, which is 100g in total. Lots of veggies, some meat, a little bit of everything.