That s an interesting comment however I would reserve that even though before I had fat adapted I had all kinds of “energy” the problem was once I got past a few minutes of sustained energy use in athletics or what ever it may be I fizzled out. That energy was of course in comparison to my sugar burning days.
Once fat adaption started I could go slightly longer each day, the cellular beta oxidation was starting to take over and the ketones were doing less and less. I might add that after I was well fat adapted(8 months in) two other things became apparent to me.
My cholesterol numbers went north and south, my HDL went south(not a great deal but matched 1:1 my trigs) and my LDL went way north.~I am a hyper responder and I would say yes cholesterol can be an indicator of fat adaption if you are trending it.
and my ketone production became minimal, again I rely on my cellular level of fat burning and not my liver.
Neither are of a concern to me as ketones at my level are not important, to be metabolically flexible is the amount of available energy is almost limitless nowadays as long as I don’t go to far into anaerobic/cardio area for extended periods.
How do you 'feel' fat adapted?
For me, it’s all about sustained energy and stamina. I have a chronic-fatigue-type problem (not caused by Epstein-Barr, so they have no idea what to do for me); and while keto hasn’t set me abuzz with energy, it has given me my stamina back.
I was able to shovel snow for several hours after the recent storm, and over the summer I was able to spend hours mowing the lawn—and all without collapsing afterward, or having to spend a day or two in bed, recovering. Of course I’d love the buzz as well, but this is plenty to be happy with, let me tell you! 
That is wonderful that you’ve had relief from your CFS with keto. How long did it take you to start feeling better?
I suffer from CFS and have been keto for 34 days. No improvement yet but I’m hanging there!
water tastes different. it’s hard to describe, but it has a thicker, more satiating feel to it. I believe this also helps with being able to/wanting to drink more. It just tastes good, and feels like it helps whoosh away fat.
It took a while. I first noticed around four months in, when I was packing up to move house and realized I could go long hours without having to rest nearly as often. But I really noticed when we bought a lawn mower last year, to save on lawncare costs, and I started mowing the lawn. I actually almost sort of enjoy it!
Thank you so much for your reply! It helps me so much to know that I’m going to have to be patient with this diet and waiting for my energy to return.
If I had the energy to mow the lawn and not be tired afterward I think I would enjoy it, too! This fatigue is life-stealing.
All the very best and continued health to you!
Right back at you. You are on the verge of keto- or fat-adaptation. Keep ketoing on to get the good stuff! 
Hang in there a little longer, it will come . For me , around the 75-85 day mark, I started to feel more like my old self. I no longer spend days in bed. Giving up caffeine, and taking ketoaid & digestive enzymes most days has really helped me transition to this WOE. If you stick with it, the metabolism will heal itself, it is really wonderful. All the best in your journey.
FWIW, I’m nearly six months in and just got HAMMERED a couple of days ago, and am slowly improving. Also coming of AD meds, so that may well have something to do with it, but it’s just letting me know it’s still there.
Thank you so much for your input! I will stick with it for sure. All the best to you as well. 
I can taste ketosis
I can feel fat adaption.
When I started I had no energy when running and needed to take frequent walk breaks. At about 3 months it suddenly changed and I was back to 100% running.
Hi Chris -
Just read your message and this is really ringing a bell.
In Keto since 4 weeks and feeling that I am very close from what you described as “fat adaptation”.
I am a cyclist and goes also 4 times a week at the gym for weight lifting.
While I do not see much impact on my strength, my bike rides are terrible: HR way above normal level, no power in legs (I can barely push 180w while this would be my warm up power normally…).
How did you manage this? just electrolytes and cutting back a bit on training? then it will resume?
For the rest, I believe I start to feel the benefits of Keto i.e. I feel better, more empowered and energised, I know I am kinder with family and relatives on a day to day basis as well, seeing things more positively…
Any other insights or feedback just to give me insights of what I should be getting ahead?
Thx much
Seb
For improving fat adaption for endurance look into Maffetone low heart rate training and adapt it to your cycling. I don’t think about ketones or autaphagy or any of that fancy stuff. I eat twice the protein recommended and 40 net carbs instead of 20 total carbs. What I also do is activity/exercise averaging 1,200 calories a day, 40-50% of daily calories and all of that, not counting the lifting, is below my aerobic threshold, meaning low enough intensity to be burning fat, not carbs. Only about 10% of calories in the diet are coming from carbs so I must be burning fat most of the time. So may be I have a heavy handed approach to keto.
So That post is several years old I don’t frequent here much anymore. I as of last year went mostly carnivore, I still eat occasional some veggies but I primarily subside on meat, eggs and cheese. I did not for the first month of keto really exercise. So most of my exercise started a month in, and I still had issues for several weeks after that point. I would say it was at least 3 months in is when I was starting to get back something I would have considered normal at my exercise level then. I used the meffatone method to great success in my terms of usage, its not a perfect system but it did work better than burning myself out on cardio every day. I tried a bunch of different things for my strength training, my goal then as it is now is not to build but to burn. So I do very slow intentional movements, I have some dumbells, few free weights, and total gym which is what I use primarily. I tried HIT early on, and it may have been too early, as it often just destroyed me for the rest of the day. I was more about working out everyday than hitting hard a couple times a week. I also always worked out fasted at least 8 hours and for a very long time more like 18 hours before a work schedule change. At my height I would workout in the morning for about 30 minutes, consume roughly 5000 calories most of which was fat, work a 12-16 hour day, then come home and ride my bike for an hour or so weather permitting(and still lost weight). I used the feast fast to great success in my eyes then. I would put a extended fast in every few weeks, did a couple over 40 hours, and rarely if ever cheated keto in general. I hit my goal weight around a year in, but my BF never hit target, I started to have some issues with joint problems at about a year and half, and suffered for a while and decided to go carnivore after reading up on the subject on my 2nd keto anniversary.
My biking is primarily mountain, I don’t compete or really go crazy as I am getting older and it hurts a lot more when I hit the ground and I don’t have the time I used to. I tend use short bursts more often than constant cadence, the thing I noticed the most at around 8 months was that I could get on my bike ride for 2 hours at medium pace on paths or roads. I would get back and had zero recovery time, never sore, and no bonking. I would do this daily when I could, a normal ride daily ride was ten miles, and did several 30 miles with out an issue at the spur of a moment. Towards the end of my peak I adopted a husky who I would tow in carriage, because he would run with me but only make a couple miles before he bonked. So I would tow him and still do the 10 miles or so with him running one or two as fast as I could pedal very often. After switching to carnivore I don’t get to ride as often and I have a lot less time, but I can still get on a bike and ride for a couple hours without any issues. I tend to bonk a little more, my blood sugar is a few points higher on carnivore but I feel even better than when I was strict keto.
So things I can tell you, take salt and lots of it, I use around tablespoon a day still. Get sun or take Via D, I have not been sick since the week after I started keto that was over 3 years ago. When I was hard core keto I supplemented with krill oil(unless I eat fish within a day) and collagen. I still take the krill oil, and via D. Water was important back then, I am about half of what I was then as I lost weight I drank less, my only vice is I got addicted to diet soda but I am working on that again.
Keto in a lot of ways saved my life, and at the very least it stopped a nose dive. I have a list of physical and mental issues that it cured and for those reasons alone never want to go back, the weight loss is why I started, but I stayed for the way I feel. Fat adaption or beta oxidation does take time but you probably have an ah hay moment like I did. After several weeks of bonking on exercise bike I tried a different approach. I would start with zero effort and work my way up to the highest setting with a constant cadence, then I was under a time constraint so it was around 15 minutes I had. I did that day in and day out for around a month(so about 4 months in) one day I got on the bike started to ride and I did not have to be anywhere so I started to watch a video on youtube about keto. Next thing I know its been 45 minutes, I looked down and I started and rode the whole time with the bike on max tension. I kept going until I could not which was another few minutes, it was then that started to understand fat adaption. That would go up a few more minutes each time I would ride till I got to the point it was no longer an issue. I have said its not a light bulb moment, its more like a dimmer slowly turning up.
I hope this helps.
Thx so much for your answer Chris.
Really appreciated and full of insights.
After 6 weeks now, I have to say that my bike rides are not improving that much… the one of yesterday was a painful turbo session. I intentionally kept an easy endurance pace but I was amazed by the low power output though I noticed that my HR was below what it used to be over past weeks. So slightly improving… Gym session are ok, although I am hitting any PR (but I lost 4 kg since I started Keto without really wanting it… mostly water I believe)
On the other hand, I clearly start to feel some positive signs of the Keto Diet. I did not enter this to lose weight but for the positive impact on health. Mental clarity and overall better mood is clearly something I can already feel (and my family as well)… and it’s giving motivation to keep going.
After 6 weeks, I sometimes feel some Keto-flu symptoms (yesterday morning was terrible, I felt like it was impossible to get out of bed, so tired…)… but I see a clear correlation between these symptoms and the lack of electrolytes or salt supplementation. As you said… I’m not going to miss that part anymore. It is crucial for going the right path with Keto.
My urine is still showing ketones to a fair level so I assume I am not using my FFA well enough and I am not fatty acid adapted yet… the process of adaptation is still going.
One thing I’d like your views on is IF. Before Keto I used to do IF 16/8 and I did not change this pattern with Keto but I am wondering if this is a good set up for a Keto Diet. Any views on that?
Again, thank you.
Seb
So the urine sticks are Ok measurement to see if you are producing ketones, the more I researched the more I realized that ketones are not something to be striving for over a long term. They are great indicator you are doing the right thing, and they are great to have an abundance of when you start out. Personal opinion here but the community pushed to have high ketones at all times and I think that long term that is not beneficial nor practical outside of diabetes. The generation of ketones is my mind after you have fat adapted fully (we are talking many months here) is a supplement and not a primary focus. Again primary focus long term is to burn fat directly, minimal ketones are generated and used. This provides a much more seamless transition to carb fuel if it happens and the transition back is not as harsh. (i.e. train low compete high) I can tell you that I avoided the cheating after a few months in after several really nasty headaches, and stomach cramps both by intentional and accidental dropping of ketones for carbs.
One thing I did develop(and part of this thread originally) with the urine sticks and cheap breath analyzer was good sense of when I am in ketosis the effect on my body is different sensation then when I am running full carivore or the feeling when I am carb burning. I also got pretty accurate idea of my carb tolerance (about 60g in a 24hour period)for ketone shutdown and when fat storage/glucose control start. Longer term i did not get the crazy headaches, or most of the stomach issues(until carnivore) when I did cheat, I used the train low compete high things a couple times on long distance benefit rides and it worked spot on.
Things I have noticed long term is my HR in general dropped, my BP dropped like a rock, and my trigs are nill most of the time I have had them checked, often less than or equal to my HDL which is fairly low too. My view is that the high HDL is a sign of a problem not a counter to the high LDL.
The ketone clarity faded, but I did not go back to the fog of my sugar days either nor the depression of it either. About once every couple months I may go south and have some ice cream or piece of cake etc, when I do I make a day of it normally maybe have some crackers or a few french fries. I will add that if I have something sugary apposed to high in starch the effects tend to small, starch tends to last longer and I often feel worse over longer period if I do feel worse. If I do that for more than a day I go through a fog and depression about 24 hours later, that typically lasts as long as my high carb days did. The other result since being carnivore is that my body when it senses enough carbs in my gut seems to want remove the meat(quickly) and digest the carbs. If I am truly carnivore for several days or weeks its rare I see the bathroom much if at all other than urine.
IF I have played all the routes there, the one that worked the best for me on a endurance level was 18/6 but in my case I almost made that 2MAD one at noon and one at 6. The workout then was 1 hour every day except Sunday which was normally a 2 hour bike ride first then a quick workout of 5 minutes or so. This was the pattern for a whole summer more or less, it was the first year I was keto. Workout am around 9 then at noon I ate my first meal and then about 20 minutes to half an hour later I would consume a high fat shake. I could then normally go until around 6 when I would normally have some cheese sticks and few cups of spinach with evo.
The best weight loss was without question 1MAD and would always eat excess fat and lower protein. This did have some side effects in I lost more muscle mass than I cared for, I would argue that was not bad thing as I did feel really good. I was working long, hard 12-16 hour days then, towards the end of that stint I would intentionally cheat early weekends so I would gain some fat for the week. I was pushing the envelope and sometimes would run out of energy which was like a bonk except worse. Thank god for HWC and macadamia nuts, those were my 6k calorie days(in one meal most days). That caught up with me when I stopped working so much, quickly i gained about 10 pounds before I got it under control again.
The two other things I did outside of exercise and meal timing to make myself feel good was to make sure I took in no pressed oils, in particular soy oil-that stuff is horrible. I know when I have had that I swell up really quickly, and I tend to feel less manly for a day or two. The other thing I did unintentional was to work in a cold environment all day long with only a shirt on, the temps vary form 37-50F depending upon were I am standing. This enabled brown fat, which not as much an endurance thing but it seem to make a difference on my BF level when I am doing that at work to this day.
Hope that helps.