Adding my personal experience...one person, tried it only once..so this is not exactly a brilliant experiment. I am re-starting fasting after a break but by 1pm was very hungry. Tried a whole avocado with 1T of Lemon Olive Oil, but an hour later was still ravenous.

Yesterday at 1pm, about the same hunger, had a can of salmon with 1T homemade olive oil mayo and was still feeling full by dinner. (Thanks teaser!) With some ground beef and coleslaw for dinner, my protein was still "moderate". For me, even after five years LC, sometimes fats just don't do it.
There have been discussions on this forum before that older people may need more protein, and an Atkins style fat fast didn't work for me either, I just seem to need more protein to prevent hunger. But darn, that avocado tasted good!