I think it would be very helpful to prominently display on the website some easily accessible links to – and/ or some guidance about – basic tools for calculating things like BMI (Body Mass Index) and TDEE (Total Daily Energy Expenditure).
Lots of people new to the 5:2 system seem to take the oft-quoted intake limits – 2000/2500 calories for non-fast days and 500/600 calories for fast-days – as ‘gospel’ without understanding the advisability of calculating their own personal intake limits, based on their individual statistics and activity levels.
The forum is so busy nowadays that any one person’s attempts to explain the principles involved soon become ‘old news’ and are buried in the back pages.

2nd, revised comment re link to calculators: Hello again, fastdiet, in your post in the ‘Helpful tools’ thread the link DOES take one to the ‘How many calories…..’ page and, there, the ‘Go straight to….’ link DOES work. That’s great. Thank you for responding so positively and quickly to the suggestion. Have a good evening (assuming you’re on UK time.)

Oh, dear! The online form takes all the details but then goes nowhere when I press the ‘Calculate’ button.

I’m using an iPad 2.

Hooray!! Bravo, fastdiet. Wish I knew as much about I.T. as you do. Great job!