Hi Bigbird,
welcome to the group.
I can’t really tell you about long-term effectiveness, as I am a relative newbie (started 2.5 weeks ago, and last week I was very unwell so ate little when not fasting, but also closer to 800 cal on fasting days).
In my opinion, if 800 calories work better and are less exhausting, you should probably go for that. I have decided that if I really can’t cope with 500, I will allow myself up to 800 but not more. That reduces the stress and it gives you some room for manoeuvre. It doesn’t have to be either 500 or 800, it can be any in between and the benefits are still there (that’s, again, my opinion – just trying not to stress myself out!).
Also, eating mostly proteins and vegs seems to work really well with me. Vegs don’t bring in many calories and proteic food makes you last for much longer.
Hope this helps! Fasting-me or any of the others surely have more advice.
8:23 pm
30 Jan 18