My encouragement is that with 5:2 it is just one day. You can fast for just one day! Think how many of the allowed 800calories you want to consume and when and what, and then go for it.

Then when that one day is over and you are tucking in to your first meal on the following day, you can think about the second fast day, and start planning for it.

All power to you.

By no means am I an expert to give advice. However from my own experience I can say that intermittent semi fasting has become a “tool” that I can apply anytime.

The 1 day semi fast of 600 calories.

How I started and what I do now.

When first attempted my first 600 calorie day. I was focused more on calories than satisfying hunger.
Or strategizing when to eat.

So I failed 2 times before having my first 600 calorie day.

My approach then became to journal both my fast days FD and Non Fast Days NFD.

I started by picking the hour of my last meal on the day before.

Semi fast days work like.
6pm last calories
Only 600 calories the following day.
At 6am the next day the fast is over.

The main point is 600 calories over 36 hours.

What I take from that is psychology, about having the confidence and patience to practice what works best.

By journaling my hunger pangs.

I learned that just for me, I start my very first fast at 10pm.
I don’t eat until 1pm the next day, of 300 calories a can of food. Because it’s easy to put the can in the microwave. And I’m less tempted in the kitchen with preparing food and measuring things, the temptation is to great to be around ready to eat foods.
So I’m in the kitchen for less than 3 minutes, and five hours later , eat another can of 300 calories can.

Then nothing till the next day.

It doesn’t exactly the 36 hour guide.

But it fits my psychology for confidence. Getting that first successful day of 600 calories as opposed to fitting the 36 hours.

The goal for me is with practice getting to the 36 hours with only 600 calories , but not on the very first attempt. But withing the 4th attempt I’ve got some experience being patient until 1 pm.

Because I know that I’m not starving, but just hungry.
I also choose to limit cheating, to 150 calorie protein drink.

The protein shakes can become a crutch,
But I’m not going to beat myself up over a 750 calorie day. So its just away of staying close to the 600 goal.
It’s still a day well below TDEE.

And with practice I start to have confidence instead of anxiety.

After the weight starts to come off.
It’s very motivating to learning from my journal entries. And after a few months with 24 attempts of the 36 hour semi fast. I go on to start focusing on changing habits on non fasting days.

Learning what sates me without binging.

I learned that on traditional eating below TDEE. My problem is I occasionally binge. And I give up on the slightly restrictive diets.

I found in 5:2
A tool for being hungry for one day.
But not starving.
And being sated for the next 3 days.

Then as time goes by as the confidence of the fasting days become doable.

I focus on the Non fasting days.
Focus on not binging, then focus on how much calorie restriction I can tolerate on non fasting days without feeling hungry AT ALL.

If I can point to one thing that worked for me was journaling what works and what didn’t.

Like not overexerting myself on fast days.
Not avoiding food gatherings, but planning on fasting days before and or after a food holiday.

Reading and commenting on the forum,. To learn new understandings that other people share with their experiences.

How much exercise to schedule and which days not to exercise.

But try not to pile it all on day 1.

That the intermittent semi-fasting is a lifestyle, that overtime we learn what is doable on fasting days and what healthy on non fasting days.

Best wishes.