The farthest I've gotten in one pop on just meat, fat and vegetables only, with just a tiny bit of fruit, was almost a month. In that month a nasty chronic yeast infection clears up, my asthma clears up, allergies way better, lost weight...all good. But still. So. Fatigued. Seemed abnormal, scared me enough to go to the Dr., he said my TSH-3 was normal at 2.69, and AM Cortisol normal at 6.4, and that, basically, was that. Well, I fell back into my old carby sugary ways, and I felt so much better. Energy again. And along with it came back the yeast problem, the asthma, the allergies, 4 pounds, looking like crap... My question is, CAN everyone get fat adapted? I loved some of those changes, but I really couldn't deal with the fatigue. I've read posts on here from people who felt totally crappy for months until they added back more carbs... I so want the benefits of the thing they call "fat adapted," but wonder: IS it possible for everyone? And how long would you wait in a state of bone weary fatigue and brain fog for that great change. Want to keep trying, but I don't know how I could do school and the rest of my complicated life with the brain fog.
It's your Reverse T3 you should be checking out (also T4, TSH and T3). When you cut carbs like that, some people fall into hibernation, and the reverse T3 is the one that shows that. The same thing happened to me btw. Paleo for a year, keto for 2 months, and then spent 6 months in hibernation. Only when I started eating up to 200 gr of net carbs daily I got my energy back. I also eat fermented foods, offal, plus kefir for my IBS, and yet I'm still not fat-adapted.
Dr Cate has an article about this: http://drcate.com/going-low-carb-too-fast-may-trigger-thyroid-troubles-and-hormone-imbalance/
And the Jaminets too: http://perfecthealthdiet.com/2011/09/high-ldl-on-paleo-revisited-low-carb-the-thyroid/
My new strategy is to go slowly down to 100 gr of net carbs daily in the course of next year, instead of cold turkey. If I can sustain 100 gr of net carbs on average daily for the rest of my life, with the right energy I'm suppose to have, I'll be happy.
Mitochondria take a long time to adapt/regenerate after a SAD diet, so adaptation might well take longer than a month - I've heard of people in their twenties taking 6 months to get sufficiently fat-adapted to feel more energetic. I am a fair bit older than that and it took me over a year to be fat-adapted enough to be able to eat less than 50g of carbs per day. Once I did, I was able to stick to it and get rid of my candida etc. I am also fairly effortlessly maintaining my weight loss of 55lb.
Medium-chain fats, such as coconut oil and butter, are metabolised differently and are more easily available for energy than other fats. They might provide some more energy during the adaptation process.
I don't know if fat adaptation is possible for everyone and I can't deny the adaptation process was tough, but for me although it took a bit of patience and persistence, it was well worth it.
I started adding coconut sugar at times when i feel tired and it really boosts my energy. I dont use a lot, but add it to my protein shake or tea. I recently made some treats with coconut flour, almond meal and coconut sugar - helps when i need to get out of brainfog fast and dont wanna prepare something. Not sure if it works for everyone but it might be worth a try?
I feel shitty in ketosis, I tried it off and on for over a year. I'm someone who has always had a consistent weight and lower body fat percentage, I think that is a lot of it - those who feel great in ketosis usually have borked metabolisms/plenty of extra body fat to burn through.
It's not a matter, though, of eating nothing but meat/fat/veggies vs eating tons of sugary carbs. I eat about 150g of carbohydrate per day, mostly from rice, potatoes, and veg. Also plenty of protein, and lots of fat (since I am trying to bulk up). I still consider myself paleo/primal.
Maybe it's salt(s) that you're missing?
Mark Sisson has a post about muscle cramp and fatigue over on mda where he raises the possibility that cleaning up your diet (no processed foods, no sodas) drastically reduces salt consumption.
Clean food prepared from basic ingredients doesd not contain much salt. Salting your food, adding seafood and seaweed, or supplementing with a suitable multi-mineral might be the answer?
2.69 is in the published range of 'normal.' However, my doc said that the current trend is they want it lower than 2. The first day I took the thyroid was amazing. I woke up and felt like I was in a Disney movie and wondering where the singing cartoons birds were. I felt refreshed. I thought 'this is what normal people feel like when they wake up.' That only lasted two days, for me; but I have a genetic condition that is unrelated (well, probably) to thyroid or lack thereof.
Paleo is not one-size-fits-all. If fat adapted doesn't work for you, add some sweet potatoes. Smothered in pastured butter. Or coconut butter.