I don't know if you mean "high fat very low carbs" by fat fasting, but It may seem hard to handle for a long time in the beginning. I started three weeks ago thinking nothing to lose trying, well, hoping to lose weight, seems going fine. Today, even though I'm on vacation at this mountain, a place hard to find food that you like, I had eggs, cheese, salami, and olives at breakfast, and that was it. I looked at the salty muffins on the table, had a bite at the end of my meal, and did not want more.
As a food muncher for 24/7, I did it. I will eat meatballs at dinner - so hot and humid here, so my body needed no lunch. So, I can eat even more protein and fat tonight.
Just give it a go for a few days, try a week if you can. See how that feels.
I remember the days having my tea with triple sugarcubes, My stomach turns if I add sugar since 2 years. So, things can change, If you find a way to motivate yourself.
Good luck, if you go for it.