> starting at ~600 calories per day--all sugar as fat and protein prevent hunger from subsiding. After the hunger subsides it's easier to taper off entirely.

I think that statement was easily misinterpreted.

After not eating you start to feel hungry. After a couple of days, that hunger will fade. Eating fat or protein will satiate that hunger but will sort of reset that timer on the hunger going away entirely.

I think the idea is you do a 7 day fast, eating a small amount of sugar during the first ~3 hungry days.