Personally, I think the maximum health benefit comes from zero calories. I'm able to function and work fairly well for the first 7 days. It's (typically) on day

Personally, I think the maximum health benefit comes from zero calories. I'm able to function and work fairly well for the first 7 days. It's (typically) on day 8 that I start to feel weak and/or sick. I've gone to a twelfth day, and by then I feel like I have the flu. Which is interesting, because it taught something about a flu. I always thought a flu did direct damage, but now I think the worst thing about the flu is the interruption of the production of normal proteins that my body needs. And exactly the same thing must happen after 7 days without food -- the body is increasingly unable to make necessary proteins. It is interesting to me how much the feeling of a long fast resembles a flu.