So I had a week of really out-of-control keto eating, and realizing it was time I just decided to fast. I was eating at night and waking up hungry. Bad sign. Yesterday was the first day. I had a few cups of keto coffee with a generous amount of coconut oil. I also added a little cayenne pepper, an idea I got from Jeanne Sigel. That did the trick. Had a cup of salty bone broth with butter in the afternoon, and then around 9 pm a cup of hot water with lite salt and a shake of chipotle chili powder. That was actually delicious and satisfying. I woke up this morning feeling great. I’m playing with my band tonight at a new place. I’m planning on continuing my fast as long as I can with a week cutoff time. Then, it’s back to feasting for a few days. Feeling my superpower today!
Spontaneous fasting good!
I’m finding that with my A-Fib, I have to feast longer before a fast, and it takes more planning.
But, I put cayenne pepper on everything as it reduces (supposedly) any stroke risk or damage from a stroke. I like the taste, but it can be spicy…
Give hot water with sea salt and cayenne pepper a try. Easy peasy and tastes good to me. I used this “cayenne tea” during a recent fast with success. 
By extension, a combination of ACV, cayenne pepper, and fresh lemon juice are the ingredients in a drink that is supposed to combat candida overgrowth in the GI tract and I’ve recently starting adding sea salt since I’m keto. I find that the combination reduces my appetite, too.
Ended my fast after 3 days. Now I’m in feasting mode. Back to fasting as soon as my metabolism kicks in. 
I’ve noticed the same thing - I was fasting even when I was cold or tired, and I’m beginning to watch for the signs that my metabolism is ready for another fast instead of sticking to some arbitrary schedule.
My last spontaneous 36 hour fast occurred after 16 oz of pork spare rib meat (no bones) and a 24 hour fast occurred after an 8 oz ribeye with 4 oz of extra ribeye fat plus some other incidentals.
I really hope this results in a more regular recycling of autophagy/rebuilding.
One big factor for me is not feeling cold when the temperature doesn’t dictate feeling cold.
The thermic effect of food from digesting protein is something that’s very short-lived, so eating one meal might result in a feeling of warmth, but if I’m cold again a few hours later, then it was a transient rise from digestion.
When my metabolism is primed and running again, which seems to occur after several days of eating normally, that trigger will last days.
Recently after I ate the 16 oz pork rib meat, I was radiating body heat for days and once a few years ago we went Pike’s Peak in Colorado where I was eating vacation-style keto and stood on the top of the peak in short pants and short sleeves in 20 degree Farenheit weather and loving it, whereas when calorie restricting it can be in the 60’s and I get so cold I’m freezing and have to wear gloves.
That happened to me last night. My fingers got really cold. That was after 70 hours or so. That’s when I broke the fast.
Update. I am on day 2 of feasting. I lost 7 pounds over the 3 days I fasted and I haven’t put ANY of that back on since starting my feasting state Sunday night. I’m eating 80% fat - twice a day - within a 6 hour window. Believe it or not I’m getting bored with food and am anxious to start fasting again. Perhaps I’ll just have bacon, eggs, butter, and cheese today and go back for another 3 day fast.
Bottom line: switching it up seems to be working for me.
Another update. I started another 3 day fast today. Started with keto coffee just like before. Had my salt-and-cayenne water (lite-salt and hot pepper in hot water) with a little butter in the afternoon, switching to the same with no butter at dinner time.
Just for fun I took some vitals:
Blood Pressure: 128/85
Blood Sugar: 66
Ketones: 1.6
I’m really liking this pattern. Hopefully I’ll be able to shed a good amount of weight before Ketofest.