i didn’t try the prolon directly but I did consume healthy juices / food and kept it around 500 calories to try and mimick the prolon protocol in my own way.
It seemed I still had the benefits of fasting because lack of sleep and weight loss was continuing at the same rate.
No but I have done PSMF for a few weeks. Its also a keto diet but low cal, I was about 750 cals a day but it was real food you can make to your tastes. Think there is a sub for it.
Edited to add it is much cheaper than this!