I don’t think anyone knows. We can switch back into metabolizing glucose at any time, but you’re asking how long it takes to accumulate enough mitchondrial damage for the metabolic switching to get stuck in glycolysis again. If I had to guess, it would be probably longer than a month, but less than a year.
How long until you are OUT of being fat adapted?
240lbfatloss
(Ken)
#12
I see we’re “Rediscovering the Wheel” on this one. This topic has been discussed in Bodybuilding/Fitness groups for decades. Detrimental readaptation that recreates anorexigenic hormonal resistance states is dependent on one thing. The recompensation and subsequent chronic overcompensation of glycogen. Same thing with fat gain. It’s only after glycogen is full that the receptors are desensitized that the body begins directing glucose into lipid cells for storage. This is also why you can eat occasional carbs for metabolic purposes with no worries of fat gain. As long as you eat them when glycogen is depleted. Fat gain and adaptation doesn’t happen unless glycogen is full. It’s merely the opposite for fat loss, glycogen has to be depleted to begin lipolysis.
Carbs have long been known to.assist protein transport into the muscles. That’s why limited amounts are consumed around workouts.
Back to the original question. It depends on how much and often you overcompensate glycogen.
JD0129
(Joe D)
#13
I really hate to ask questions that have probably been answered a million times but I’m fairly new to this. I feel like I’ve done my homework and everything seems to be working. I test ketones almost daily and have had positive readings pretty much since I started. I’ve been strict and I’m happy with results so far… however!
No matter where I look (google, YouTube, Reddit, etc.), I either can’t find or I don’t understand the “fat adaptation” part of all of this.
How do I objectively know I’m fat adapted? Meaning, for sure? I’ve read that you “just know”. That seems silly and subjective.
Once fat adapted, does anything change as far as routine? I’ve read that you can ease up on how strict you are with carbs but I’ve heard people say that they’ve been keto or in ketosis for years?
I can probably come up with at least 10 more questions specifically about fat adaptation but I guess we’ll start there.
Background… I started about 2 months ago, I’m fairly active (workout 6 days a week), goal is to only lose about 5-10lbs, currently sitting around 12-13% bf, I am strictly “clean” keto, I test ketones regularly.
Thanks in advance!
Rclause
(Scott)
#14
You can save a lot of grief if you just order without the bun from the get go. This has become natural for me to the point that I can’t imagine consuming a burger with a bun now and not feeling bloated and stuffed. It is also fun asking for extra bacon too. The fries are a mind over matter thing. You can either get them and share with the table (but not eat any) or just say hold the bun and fries. In more of a restaurant setting they will substitute broccoli for the fries if you ask. I was on vacation and felt bad that when the burger came it had the fries that you speak of and I caved, I ate two very small ones.
PaulL
(Bacon is a many-splendoured thing)
#15
There’s no known way to measure fat-adaptation, so it can only be determined subjectively, but there are a few indicators. First, let me point out that ketosis begins almost immediately after carbohydrate intake drops low enough, because serum glucose and insulin drop, and insulin is the main regulator of ketogenesis (although glucagon plays a role as well, under the right circumstances). The process called fat-adaptation is a cellular adaptation to metabolizing fatty acids in place of glucose and even ketone bodies, thus sparing the glucose and ketones produced by the liver for the organs that require them.
At two months in, you are probably fat-adapted. Part of fat-adaptation involves mitochondrial healing, part the ramping up of the production of some hormone or catalyst, the name of which I forget. Dr. Phinney has a great description of all this on the Virta Health site, if you can find it. I forgot to bookmark it, myself. But these changes take time, which is why fat-adaptation lags behind nutritional ketosis. One useful marker is that people who exercise notice a drop in performance when they embark on a ketogenic diet, and once they reach fat-adaptation, their performance returns to pre-keto levels, and sometimes even exceeds that.
Otherwise, you’re left with a sense of energy and well-being as your primary markers. People occasionally find they need less sleep, so they might find themselves rising before dawn and cleaning the house or working in the yard, for example. Or they might find themselves taking up exercise (shudder!) to have something to do with all that energy.
You can explore how much additional carbohydrate is safe for you to eat above the 20 g/day limit, but we advise waiting till fat-adaptation for that. Where exactly your carb threshold lies is individual and depends on how insulin-resistant you are, for one thing. How advisable exceeding the 20 g/day limit might be in your particular case would depend on whether you are a sugar/carb addict, how well you feel, how much you miss some particular carbohydrate-rich food, and so forth.
JD0129
(Joe D)
#16
I’ve read this a million times… if you’re kicked out of ketosis, you have to “start all over”. I read my ketones with a meter. According to the meter, it’s been reading ketones for a solid 3 weeks. I’m only counting 20-25g carbs today and I did an hour long HIIT session this morning. I say 20-25g because I had a salad at a restaurant today (iceberg lettuce, about an oz of tomato, a little onion, a few Tbsp of ranch dressing, some cheese, and 6oz of grilled chicken. Also had about a 1/2 cup of cottage cheese. It wasn’t anything fancy… pretty boring for a restaurant actually. But I guessed the sizes here. My other meal was prepared in my kitchen and measured to the T. Reading ketones tonight and it reads “Low” which I’ve never seen. I’ve seen it read as low as .1 before. So, low to me means 0? Let’s just say that’s the case…
Hear me out… let’s say I’m 6 weeks in ketosis, no cheats, always reading with a meter, solid. But not fat adapted yet. Then I slip… let’s say I have 60g carbs one day. You mean to tell me that I now have to “start over” and go another 6-8+ weeks to get fat adapted? Those initial 6 weeks are gone from one slip up??
Logan_Rezvani
(Logan Rezvani)
#18
Great Question! Based on my experiences I believe that once your body has learned to efficiently use fat as fuel it will be able to revert back to that state whenever needed rather seamlessly.
My experience with this is as follows:
It took me about 6-8 weeks of being in Ketosis until I felt my body become fat adapted. I stayed in Ketosis for another few weeks after fat adaptation. However, I reverted back to a normal and more balanced diet which included normal amount of carbohydrates. I maintained the normal carb diet (as much as 200 grams a day) for a period of 5 weeks which very obviously took me out of Ketosis. After this five week stretch I decided to get back in to Ketosis and quickly cut the carb intake to around 20 grams a day.
There was a profound difference between getting into Ketosis without being fat adapted (first time) and getting into Ketosis once fat adapted (second time). The first time, I experienced several day long Keot Flu which as you know comes with a severe headache and other painful side effects. This was due to my body struggling and learning to use ketones as an energy source versus glycogen. The second time however, was 100% painless, no keto flu, no head ache and not side effects of any kind whatsoever and I believe this is because my body had previously learned how to use fat for energy and so when the time came it was able to transition from carbs to fat seamlessly.
Good Luck
Logan
atomicspacebunny
(Bunny)
#19
From the details in your description with the type of lifestyle; weight lifting, cycling, fasting etc. and the time you have been on the ketogenic diet it would take a very long-time for you to be kicked out of being fat adapted irregardless of whether or not your seeing ketones on a meter because you are going into ketosis when you go to sleep at night any way.
When people quit going into ketosis, when they go to sleep at night is when the trouble starts that’s why they need to go on a ketogenic diet?
That carb intake your noting is nothing compared to your lifestyle; your actually oxidizing glucose/sugars or carbohydrates because of your muscle volume so it is highly unlikely it will be stored as fat!
I do not see even a remote possibility of you getting kicked off any kind of wagon in your case because you appear to be in really good (excellent) physical and metabolic shape.
Rclause
(Scott)
#20
Fat adaptation is not a switch that gets flipped on. It is more like a slow gradual slide toward it. Think about it I don’t think I have ever heard someone say “I became fat adapted on ____date.” Therefore the opposite may be true, you don’t go out of or away from adaption like a switch being turned off, you just get a little further away.
amwassil
(Michael - When reality fails to meet expectations, the problem is not reality.)
#21
Until now, testing of RER (see second link below for discussion) was pretty much limited to big, bulky expensive equipment. We’re on the cusp of cheap home devices. So the days of guessing whether or not you’re ‘fat adapted’ are soon over. Still waiting for my device to arrive. When I purchased in June I was advised of November shipment. Just fired off a query asking if shipping is imminent or not.
ctviggen
(Bob M)
#22
I’ve found that after almost 6 years of low carb/keto, I can eat things like ice cream, and a lot of it, 1-2 times over a weekend, and not only be fat adapted, but be in ketosis on Monday. If I didn’t know what carbs did to my blood sugar and the like, I’d try to test to see how long it took me to get completely not fat adapted. Too many variables, though, like working on the house. Right now, I’m running from the basement to the second floor and back again, all weekend. With that kind of work, carbs are getting used up too quickly.
I bet type of carbs also play a role. Ice cream tends to make a short, quick peak, whereas pizza makes high blood glucose for a long time. The AUC (area under the curve) of ice cream is much smaller than the AUC of pizza. I’m sure this affects things.
amwassil
(Michael - When reality fails to meet expectations, the problem is not reality.)
#24
Me too!
Shinita
#25
I’ve heard such things. I got fat adapted after 7 weeks, quite suddenly. At least I can’t imagine what else it could be. The changes were great (in more than one meaning).
I’ve heard it’s gradual. Maybe it changes or it’s different for others, I never did keto for very long, only for months. But many people notices a big difference somewhere around 3-8 weeks. Surely not all, I experienced changes people have much earlier due to being in ketosis.
About the original question… It’s somewhat a mystery I think but as many of us feels different when fat adapted, we can take an educated guess, at least regarding our individual case.
I feel nothing or close to that when I go into/out of ketosis. Sometimes I feel something but I usually look at my carb intake and weight to take a guess. But fat adaptation is different. It can’t be 100% but I am sure enough about what happened with me.
So, fat adaptation changed my hunger and satiation quite drastically. I went off keto soon and continued my low-carb lifestyle with the occasionally carby day. It was fine, the changes stayed with me and I lost fat easier off keto but fat-adapted than on keto without fat adaptation. Both is the best, I don’t know why I couldn’t stick to keto but I came back from time to time and it was obvious to me I always will.
Years passed and I had carbier times too, not just days. Probably low-carb but with too much carbs. And if I managed to avoid severe carb poisoning, I started to feel my hunger getting stronger again. My fat adaptated hunger is very soft unlike my old one. I had something in between, I dropped my carbs asap and my hunger got soft again.
Then OMAD came and my hunger got rare. Keto, OMAD and fat adaptation all have some effect on my hunger and easier, longer-term satiation. I could try out keto without fat adaptation only once, it had no effect on them but now there’s a difference. So I combine all three now and I am glad fat adaptation seems to stay with me. If this type of hunger means that.
Janie
(Jane)
#26
I don’t have any personal expereince because I like the way I feel on keto too much to go off more than an occasional meal.
But going by some of the posts I’ve seen on the board where people went off keto and came back several months later and struggled a bit, I would say MONTHS, not days or week to lose your fat adaptation.
Now, you can gain weight pretty quick eating too many carbs but it is mostly water and will come back off if you go back to keto. But that’s not the same as losing your fat adaptation.
I know the few times I measured my ketones when not fasting, but the day after a higher carb day I was surprised at how fast I was making ketones again. You really do burn the carbs up quickly - the key is can you get back on keto without the hunger monster rearing its ugly head. If so, then still fat-adapted in my book.
Alecmcq
(Alec)
#28
Guys
I have a late n=1 entry to this debate. I was solid keto for 2 years ish from 2018-2020, but then fell badly off the wagon and have tried a few times to get back on.
Since a few weeks ago, I have been on my latest attempt to get back on, and I have been focussing on fasting first, as some other approaches didn’t work for me.
It has been a good 18 months since I have had any lasting period on low carb/keto. Have I lost my fat adaption? Nope. I am doing 42 hour fasts twice a week with absolutely no trouble at all. If anything easier than when I was full time keto. At the end of a 42 hour fast, zero hunger.
Maybe it is because I have lots of new fat to burn? No idea, but in my case my fat adaption has not diminished at all despite eating a carb laden diet for 18 months.
Cheers
Alec
OKina_Alford
(O Kina Alford)
#29
I’ve read this entire thread looking for the answer you just gave. I was strict keto for about 2 years…definitely fat adapted…But after about 6 months of being off the wagon, I just cut out the carbs again and I was curious as to whether I am still fat adapted or will have to go through the entire process again. I have only been back on for 2 days and I have always (when doing keto) eaten 12 net grams of carbs a day. In these 2 days I haven’t felt any fatigue and my workouts have been fine, so I think I may still be fat adapted, but was hoping to get some confirmation.
lfod14
#30
Same here, as long as you don’t go back to carb binging it definitely seems we keep the metabolic flexibility to go right back to burning fat for fuel. I do TKD now so I have about 30g carbs preworkout and sometimes after, usually once or twice a week I’ll do a half descent carb up (only good ones) and when I decide to pull them again there’s zero pushback, I deplete and start burning fat again, no keto flu, no energy issues, no nothing.
Kage
#31
That’s amazing. I fell off and am getting back on again almost exactly how you did. Thank you for this.