Peter Attia previously fasted for seven consecutive days every quarter using only water.

“About to embark a week of “deep” nutritional keto, to prep for one week water only fast...”

“I did so well all week going low carb in anticipation of my 3 day fast coming up tomorrow.”

“Nope... I will go from fasting week, back in to strict keto for another week. In other words, 3 weeks as follows (1 week each): keto-fast-keto.”

“that was mostly self-preservation I know from previous attempts at fasting that to go into a fast out of a high carbohydrate state is a little more painful because the body hasn't quite ramped up the process of making ketones and obviously that becomes the most important thing that's happening when you're in starvation so that's sort of why I did it and then as at the front end and at the back end it was actually this is not a scientific reason was I wanted to ward against guard against the risk that I was gonna go apeshit on the refeed and just like go any burgers and pizza everyday so I was like well if I force myself to go into ketosis as I exit this fast I will least continue to eat in a reasonable manner”

“I used to do a thing where I fasted seven days every quarter so four times a year I would just do a water only fast”