The fasting journal · matched to fast day 15
Day 15. Black Coffee On A Water Fast, The Honest Version
Day 15 opened with a confession. Not a dramatic one. A half cup of black coffee.
24.3 pounds in 15 days
The scale said 204.3 this morning. Started at 228.6, so that is 24.3 pounds gone in 15 days, another 0.7 since yesterday, 10.6 percent of my starting weight. The pace has settled into that steady 0.6 to 0.9 a day rhythm and the composition numbers keep moving the right direction, body fat percent down from 42.3 to 35.6, muscle percent up from 34.5 to 36.1. Every reading is on the bloodwork page.
And the sleep experiment worked. On day 14 I moved the Celtic salt and electrolytes from the afternoon to the morning, after three straight nights of waking up to go to the bathroom. Last night, quiet. Same glass, same salt, different clock. That is what listening to your body looks like, small signal, small change, watch what happens.
The coffee confession
Yesterday I had about half a cup of black coffee. And I gotta tell you, wow. It immediately gave me a jump, gave me a boost. Not to mention it really tasted good. Fifteen days of nothing but water makes half a cup of coffee taste like an event. It is good to have something to drink other than just water.
Here is the honest version, because this site does not do the polished version. Plain black coffee has basically no calories. It does not stop fat burning and the strip below shows what my ketones did about it, which is nothing.
Still parked at the top of the chart, where it has been since day 8. But a purist water fast means water only, so every cup goes in the daily sheet and the sheet is public. This is my version of the fast, on camera and on the record. Caffeine on a completely empty stomach hits different, half a cup did what a full pot used to do, so if you fast and drink coffee, respect that.
No, this is not my first fast
The most asked DM this week, is this your first fast? No. I have been fasting for about 15 years. It started with three days. Then five. Then 10 then 20. Then I moved up to 40 days and I have done an 83 day fast before this one. Now we are doing 90.
How was I able to do this? Really simple. You gotta listen to your body, listen to what it needs, be in harmony with it. That ladder took me a decade and a half to climb and this attempt still runs with a doctor, baseline bloodwork before day one and labs every month. That part is not optional at this length, for me or for anybody.
Fifteen X marks
Fifteen down, seventy five to go. Halfway through the first month of three.
That being said, I am gonna let you guys go. Have a good day. Cheers.
The 90 day fast is doctor supervised with monthly bloodwork. Extended fasting is not something to attempt on your own. Talk to a doctor first.
Quick answers
Can you drink coffee on a water fast?
On a strict water fast, no, water only is the definition. In practice many long fasters, John included, allow an occasional cup of plain black coffee. Black coffee has almost no calories, so it does not trigger an insulin response or stop ketosis and John's ketone strip stayed parked at the top of the chart right through his coffee days. The honest rule is transparency, John logs every cup in his daily sheet and this site publishes it. What breaks a fast is anything with calories, cream, sugar, sweetened drinks. Caffeine also hits harder on an empty stomach, which is why half a cup gave him a noticeable jump.
Does black coffee break a fast?
Metabolically, plain black coffee does not break a fast in any meaningful way. It has about 2 calories a cup, no sugar, no protein, nothing that raises insulin. The fat burning and ketosis machinery keeps running and John's readings prove it, his ketone strip has read at the top of the chart since day 8, straight through the days his sheet says coffee. Definitionally, a pure water fast means water only, so if you drink coffee you are doing a modified water fast. John's answer is to log it and say it on camera rather than pretend.
How long has John been fasting?
About 15 years. This 90 day attempt is not a cold start. He began with 3 day fasts, moved up to 5 then 10 then 20 then 40 days and completed an 83 day fast before this one. That ladder matters. His body has had years of practice switching into fat burning and he knows what his own warning signs feel like. It is also exactly why copying a 90 day fast without that history and without a doctor watching is a bad idea. He built up over a decade and a half and even now his fast runs with baseline bloodwork and monthly labs.
Did moving electrolytes to the morning fix the sleep problem?
Yes, at least on night one. John started Celtic salt and electrolytes on day 12 as an afternoon glass and woke up every night after to urinate. On day 14 he moved the same glass to the morning and last night the wake ups stopped. Sodium holds water for a few hours before the body releases it, so the timing of the glass decides whether that release lands in the afternoon or at 2 AM. Same salt, same amount, different clock, better sleep.