I may at some point add some carbs back in once I reach my goal. But your body doesn't need carbs. It needs protein and fats. Your brain can operate very well on ketones, in fact, there are studies that show it prefers ketones to glucose.
As for what I eat,etc. I started with 5:2, eating "normally" 5 days and doing 2 36 hour fasts per week, as in the fast diet book. That worked ok but seemed to taper off. So then went to the Fast Beach Diet, which is 4:3, 3 fasts and Atkins type eating for 6 weeks.
The more I read, though, the more I realized how bad carbs affect me. All the women in my family are diabetic, both grandmothers had amputations, and my mother has dementia. Reading about castings affect on insulin, carbs effect on it, and seeing how good I was doing, I just decided to go all in.
I researched all the different fasting regimens out there, and the eating plans, and I liked the Lean Gains method the best (16:8), zinc It works easily into my schedule. So I chose that fasting plan.
For eating, I knew carbs had to go. I went slowly, first dropping all bread, even whole wheat, except for once a week or so. Then dropped a little more. I was eating salads every day, twice a day, and it was ok but I really am more of a meat person. So I dropped that.
So, my typical day (I do still have one free day to eat whatever I want, which is alot less than it was !):
"Breakfast" 8 am deviled eggs (2)
Lunch around 12: whatever meat I made double of the night before...chicken breast or steak or pork chops FRIED in olive oil, lots of spices, usually with grilled onions and sour cream!
Dinner around 4 or 5: fish, chicken, whatever meat I bought (local grocery store has a "pick 5" for $20...just enough for 2 lunches/dinners for me. Again, fried in olive oil, seasoned. Maybe a small salad once a week if I feel like it.
Sunday brunch I eat a little more variety but still focus on meat and good fats. Snacks can be a handful of nuts, an apple, something like that.
I guess in a way, I am doing 2:5 instead of 5:2! But it suits me and it works. I do take a lot of supplements (vitamin c, D, potassium, magnesium, fish oil).
Everyone is different and you have to experiment to find what works for you. There is a ton of good information out there. I strongly recommend reading all the blogs on Intensive Dietary Management, and the book "Good calories, Bad calories". Those two were pivotal for me.