I just updated my previous post with more info about the macronutrient ratio. The protein is pretty low and I've heard that too much protein will kick you out of fasting mode.

Carbs are highish but not super high. I don't know if there is a specific reason for that carb number, or if it's chosen just because of the standard fear of fat, so trying to keep fats lower would imply carbs higher.

I think some of the comments at Mark's site reference Dr. Atkins's Fat Fast which might be similar except, of course, much higher in fat and lower in carbs. But the calorie count seems similar between the Atkins and Longo fasts.