Here’s what the RMR measurements were on 3/1 just before I started fasting.
Predicted RMR 1730
Measured RMR 2363
TDEE Sedentary 2599
TDEE Lightly Active 2836
TDEE Moderately Active 3190
TDEE Very Active 3426
TDEE Extremely Active 4017
I would say I’m lightly active this week due to some business obligations… so 2800 cal. Assuming it’s all fat (I know it’s not yet), that 311g or around 0.7 lb…
That’s my best estimate anyway
It really will be interesting to see how many pounds of fat you lose per day at the end of the fast and after a refeed to normalizes hydration. You’re starting out with an Olympic level RMR or 2363, which would suggest a rate of >2/3lb per day, however it’s not quite that simple for guys like you and me. It appears that people who fast on a serial basis develop a metabolic adaptation that drops RMR precipitously. The first day drop can be mitigated by a 10-14 day period of refeeding (which I think you’ve just done as well) but it comes back quickly. My working theory is that the drop in RMR is the result of a mild adrenal resistance to epinephrine and norepinephrine that undermines lipolysis efficiency.
This is the daily RMR chart of my friend primal.peanut over at Dr. Fung’s IDM clinic forum. He bought a Korr Metacheck indirect calorimeter to track his RMR daily. He lost 75lbs in 5 months doing 2Feast:5Fast cycles on a serial basis. His RMR goes to 2400kcal/day on refeeds but an average person his age/height/wt has an RMR of 1700kcal/day. His RMR chart does not look anything like the RMR chart in Dr. Fung’s book or anywhere else for that matter. The grey bars represent hours fasted, the blue dots are his RMR. The RMR is measured on the left y axis, the other metrics are measured on the right Y axis. His RMR can drop 400kcal on the first day of a fast. A person doing their very first fast will have an increase in RMR for the first 4 days. That’s the difference between doing your first extended fast and your 20th. He finds that his feeling of “coldness” correlates almost perfectly with the drop in his RMR. We’re testing strategies to mitigate the steep slope of the RMR decline.
I’m trying to talk him into buying a Keto Mojo so that he could track GKI like you do @Karim_Wassef. I’m curious to see how GKI correlates to RMR on a daily basis. The cheapest way to track RMR on a daily basis costs $3,500. If we could correlate GKI to RMR, that would be pretty awesome. 
I just bought a Korr CardioCoach CO2 indirect calorimeter; it’s currently being calibrated at the Korr facility in Utah. I’ll have it in 2 weeks. I’m going to buy a Keto Mojo and start tracking my RMR, GKI, Weight, and Kcals, and resting heart rate daily. I’ve been doing 3Feast:3Fast on a serial basis for 7 weeks so it’ll be interesting to see how my RMR pattern compares to his.
I bought a 2 year old Korr CardioCoach CO2 from a Phd student studying Nutritional Sciences at the U of W. He’s upgrading to a Parvo metabolic cart. I spent a lot of time talking to him to understand exactly what I was getting before I pulled the trigger. I paid around $4k all in. A new one runs around $12,000. Mine is a bit overkill, because it can also do VO2 max, and in addition to having an O2 sensor, it has a CO2 sensor so you can do respiratory quotient. It also comes with software so you can dig into the data a bit rather than just getting a single number readout. The software alone costs $1,000.
You can buy a great unit called a Korr Metacheck for around $3,300 that does everything you need. That’s what a lot of DexaFit facilities use. There is also the cost of consumables however. The breathing tubes cost $7.00-$10.00 each but although the are meant to be disposable for clients at a clinic, you can get multiple uses out of them.
Sometimes you can pick one up on ebay for a good price. There was a great one that went for $800 just recently that I almost bought. If you go the Ebay route, it’s important to note that the O2 sensors only last 20-24 months before they need recalibration. Recalibration can only be done at the Korr facility, and they charge $1,100 for the first time for a new owner, and then for subsequent recalibrations you pay $395. Almost all units on Ebay will have an expired O2 sensor. Ideally, you want to buy from the original owner, not a used medical device wholesaler so you can talk to the seller and understand exactly what you’re getting. It’s still very much a roll of the dice though.
Woohoo… hit 4.4 ketones at 41 glucose.
That’s a GKI of 0.5 so that’s autophagy. Five days in… such an efficient body.
Given the low glucose, I have no symptoms. No tingling fingertips or shakes. Perfectly steady…
It was very difficult to get a drop of blood out though.
Day 1
25% (bf%)
193.2 lb (total)
144.9 lb (lean)
48.3 (fat)
0.4 (morning ketones) -> 1.8 (night)
82 (morning glucose) -> 73 (night)
Day 2
23.6% (bf%)
186.2 lb (total)
142.3 lb (lean)
43.9lb (fat)
0.6 (morning ketones) ->1.1 (night)
73 (morning glucose) -> 51 (night)
Day 3
22.9% (bf%)
182.8 lb (total)
140.9 lb (lean)
41.9 lb (fat)
0.6 (morning ketones) -> 1.0 (night)
81 (morning glucose) -> 71 (night)
Day 4
22.6% (bf%)
181.8 lb (total)
140.7 lb (lean)
41.1 lb (fat)
1.1 (morning ketones) -> 1.9 (night)
68 (morning glucose) -> 61 (night)
Day 5
22.5% (bf%)
181.8 lb (total)
140.9 lb (lean)
40.9 lb (fat)
2.9 (morning ketones) -> 3.8 (night)
59 (morning glucose) -> 64 (night)
night)
Day 6
22.3% (bf%)
180.8 lb (total)
140.5 lb (lean)
40.3 lb (fat)
3.1 (morning ketones) -> TBD (night)
55 (morning glucose) -> TBD (night)
Lost 1 pound with 0.6lb fat and 0.4lb lean. I also went to the gym, sauna and UV yesterday then followed by a cold shower so it may have been a little too much. I didn’t do an ice bath though.
I am wondering what that 0.4lb lean is. I’m hoping it’s skin and connective tissue but that seems excessive. Probably water from less blood.
Ketones and glucose broke new levels this morning with the first day over 3 and in the mid 50s. So that feels quite good. GKI just at 0.99 … was hoping to see it stay at 0.5 but it’s morning and another day of progress is ahead of us.
I’ll work on the updated GKI chart today and post it.
Wife is unhappy with my fasting already. My longest historical fast windows are 12, 7, 5, 3, 2 and 1. So this is inching into the number 2 slot at 6 days once this day is complete. Weekends are tougher because it’s family time and cooking / eating is part of that.
Keep the encouragement coming 
Once we’re through the weekend, it should get calmer again
Thanks!
Here are the updated views. I decided to go semi-log on one scale to better capture low GKI variation.
Really shows how much you can gain even on Keto. But I consider that healthy gains!
Not sure if the second plot is the best way to display fat change vs. GKI over time, but it’s one way.
Hit 46 glucose and 5.0 ketone so got to GKI of 0.5 again. My target is to get to 0.4 next. Don’t think it’ll happen today since I’m gearing myself up for the ice bath.
I’m feeling “hollow”, not hungry. Like I’m missing something and my mind is trying to convince me that macadamia nuts will fill that hole. It’s really not hunger, more like anxiety and a disruption of my peace of mind. This usually happens on day 3, but this is day 6.
I’m considering some major life changes and I was hoping that the fast would help me be calm and clear my mind. I am calm, but not clear just yet. High ketones usually give me both but it might just take more time to get there this time.
Ok. Ice bath was rough but after 10 mins of breathing exercises, the shivering stopped and I was able to be calm and actually felt warmer. I think I started generating a thin layer of warm water against my skin and would need to move around a bit to slough it off… I lasted a total of 30mins this time (previously only managed 20mins).
Now for the interesting part…
My glucose of 46 and ketones of 5.0 before dropped significantly (both did) … ended at 36 (!!!) and 3.8. No shaking or other signs of hypothermia or hypoglycemia… GKI still at 0.5 because of the ketones dropping so hard.
My iPhone app freaked at the glucose entry of 36. That’s the lowest I’ve experienced but it’s also the first time I do an ice bath while fasted for 6 days. So a day of firsts. Curious how I’ll end up in the night measurements.
Funny enough, that hollow sense of missing something seems to have gone. Maybe “mortal dread” that comes from ice water makes such silly things evaporate?
I know this is turning into a bit of a data and thought diary but it helps me push through.
Let me know if you have any feedback or thoughts.
Glucose is 36??? That seems really, really low. I don’t mean to be a Debbie Downer, but I think that’s low enough to worried about. Is it rising now that you’re out of the ice bath? That’s well into hypoglycemia territory…
I’ll measure before sleeping tonight. I feel fine. No shaking or slurred speech or even irritability.
Strangely… I feel “full” as if I just ate. Bizzare.
For the GKI can we say the the morning readings are more indicative than the night reading?
I don’t think so. I see it as an integration over time. The morning GKI is a measure at one point in time, but I suspect that if I measured it throughout the night, it would still fluctuate, especially in the last hour of sleep.
ok. Ending the night with a Glucose of 56 and Ketones at 4.1, so GKI of 0.76. Better than yesterday’s night numbers, but not at target just yet.
Also took a lot of salt and water to make sure I was in good shape after my harsh ice bath results. We’ll see what tomorrow will bring.
Day 6
22.3% (bf%)
180.8 lb (total)
140.5 lb (lean)
40.3 lb (fat)
3.1 (morning ketones) -> 4.1 (night)
55 (morning glucose) -> 56 (night)
Day 7
21.9% (bf%)
178.2 lb (total)
139.2 lb (lean)
39.0 lb (fat)
5.2 (morning ketones) -> TBD (night)
53 (morning glucose) -> TBD (night)
Ok… day 7 and this is the first significant change since the original 3 day flush. Total weight lost is 2.6 lbs with 1.3 lbs from fat and an equal lean mass loss. Not sure what 1.3 lbs of lean mass comes from but I expect it’s connective tissue and fluid mass again.
I was especially worried about losing muscle and hopeful that I’d lose loose skin but I don’t have anobjective measure until the DEXA coming up in 10 days. I am taking Leucine to help some gains from lifting…
Nice morning glucose and ketones of 53 and 5.2 so GKI is 0.57 which is a morning record so far. Going to try to take it easy today.
Midday on day 7 at 45 glucose and 5.9 ketones. That’s gets me to the target goal GKI of 0.4! 
I’m not feeling as energetic today. More lethargic and sleepy physically but mentally still alert. Little more irritable too. I’ve tried some light weightlifting, but it’s not enough. Going to do front and back ice packs to see if I can’t stimulate more energy extraction.
I would expect that near 6 ketones should be tons of energy - just not feeling it yet.
No hunger. Just dispassionate lethargy.
Here are the updated charts & tables:
The ice packs helped a bit with energy - and I’m still trying to take in more salt and water to deal with the fasting chill.
I am concerned with the large lean mass loss in one day (1.3 lbs) in spite of the large bf%.
Any ideas?
Here’s my hypothesis… I think the first ~4 lbs of lean mass loss (2.6+1.3+0.2) were actually remains of digestion that slowly moved out of my system over the first three days. This includes fiber that ferments in the gut. That means it’s not really “me” losing lean mass, but it’s me “eliminating” all digestive matter. I’m trying to say this as clinically as possible, but I’m sure you guys understand what I’m saying… So those 4lbs don’t actually relate to lean mass loss… just bad measurement.
The last ~2lbs though are more likely related to real lean mass loss in blood volume, skin, connective tissue, glycogen, etc…
Feeling a bit better. Glucose 39 Ketones 6.1 so GKI of 0.36.
I expect it’ll go up a bit before the end of the night but that’s right on target. Still surprised it took 7 days but hopefully I can keep it up.
Wife is cooking some of my favorites to entice me but I’m still not hungry.
you guys have been pretty quiet since I started sharing my plots and tables… too much info? too geeky? any advice or feedback?
