Took a 4 mo break from keto over the fall season, how long to get back in to fat adaption?


Hi, this is my first post here so I will give some more info than necessary for introductory purposes. I have done some successful keto dieting where I have lost a decent amount weight (totaling about 40 lbs at this point.) About 4 months ago I decided since I wasn’t losing weight (currently my main reason to be on this diet) and getting burned out on some of the same old keto food, which made me do some not so healthy choices (bacon cheese burgers, no bun, jerky, almonds, and not enough veggies) so I switched back to the SAD. I gained about 15 lbs in 4 months.
I am ready to get back into ketosis and fat adaption but I am wondering how long it will take? I did a one day fast to help, but I hate fasting and only went 24 hours this time (I did 7 days water/dry fasting last time and I was full fat-adapted after those days.)
Since I have been fat adapted somewhat recently, can I get back into fat adapted state in under a week? Or did I completely reset my body by eating pizza and all that fun stuff for 4 months, necessitating a few weeks to get back into burning fat?

(Michael - When reality fails to meet expectations, the problem is not reality.) #2

Do it and let us know. I suppose it depends on how long you were keto previously. Weight is a symptom of multiple metabolic issues, which may complicate your specific experience. Four months back on SAD seems likely to have reset your metabolism to what it was before. So you’d essentially be starting over again from the beginning. Or maybe not.

(Ken) #3

It depends. See how many pounds of water/glycogen you drop in the first couple of weeks. Your weight gain was probably mostly glycogen. Even a four month break won’t cause you to totally lose your adaptations, so you should have a fairly easy time picking things back up. Any real fat gain could have been easily prevented by throwing in a few keto days during the week to prevent your glycogen levels from overfilling.


Good question, tell us if you figure out the answer!

I am pretty sure it’s not very easy to lose fat adaptation, at least for me, at least those big changes I think due to fat adaptation and came suddenly after 7 weeks on keto. I never fully lost those benefits, they got weaker when I ate much carbs (and I stopped that, I love the changes) but that’s way, way lower for me. I usually do low-carb off keto, some carbier days now and then and it seems to be fine.

Months of high-carb, I think it probably ruined your fat adaptation but I don’t know if it will be easier to get it back now that you had it not very long ago. Probably, to some extent. But it’s all your some vague guess without anything backing it up, I just extrapolate from my N=1 case and just guess that my sudden changes were due to fat adaptation but what else could that be?

(Windmill Tilter) #5

This is really outstanding! Your metabolism is definitely firing on all cylinders if you only regained 15lbs on 4 months of SAD. Assuming you regained 5% of your bodyweight in water when you left ketosis, that would mean you only gained about 6-7lbs of actual fat. That’s actually quite impressive given that it was over the course of 4 months, and it included holiday eating.

Provided you’ve been eating a lot of fat on SAD, it shouldn’t take you more than 3-4 days if you keep carbs under 20g. Fasting will expedite things like you said, but there is no point doing it if you don’t enjoy it.

Make sure you’re getting lots of salt and drinking lots of water along with it.

If you think of it, post back with how long it wound up taking for posterity’s sake. Doubtless there will be folks that have this same question in the future.


This is day 4 and I have lost about 1.5 lbs each day so I am burning the leftover sugars and losing water weight as expected. My old keto strips don’t work anymore so I’ll have to Amazon some new ones so I can get an idea of where I am, but for now I feel like I am rapidly going back into that desired state. I only water fasted for 24 hours but I continue to IF 6/18 in hopes that will help.
Cutting out the crap I’ve been eating has made an obvious impact but I will keep updating as progress is made. Thanks for all the comments and support!


I had a year on strict keto & daily IF dropping 70+lbs. Then, after my summer vacation last year I got lazy and ended up lower carb (probably 100-150 carbs per day) although I still stayed away from bread, rice, pasta, potatoes, sugar but incorporated too many calories & alcohol. I ended up putting on around 30lbs by the end of the year!
For the last 2 weeks I’ve gone back to strict keto & IF/OMAD (20/2) and lost 14lbs of that.
My keto sticks aren’t changing color at all so I can only assume the my body has switched back quickly into fat adaptation (or maybe my keto sticks are too old!).

(Michael - When reality fails to meet expectations, the problem is not reality.) #8

@Craig1973 Keto stix have a useful life of about 6 months after you open the container. Testing positive for ketones does not indicate fat adaptation. Cutting carbs forces your metabolism into ketosis, which happens quickly. Fat adaptation takes time for various cells and organs to utilize those ketones and fatty acids efficiently. If those keto stix are still accurate, the darker the colour the more ketones (primarily acetoacetate) are just being dumped rather than utilized. With your previous experience, I suspect you will return to efficiency fairly quickly. Best wishes.


The keto sticks came and I am registering very purple so I am producing ketones like mad, but possibly not using them efficiently yet. That is why I got them so I could get an idea of what my body is doing, and that dark purple is always encouraging when getting back on the horse. I continue to weigh less every morning, and will have a blood testing device arrive tomorrow so I can report further on actual adaption.
Tomorrow will be one week, I did one day of water for 24 hours, another day i only ate the one meal, and the rest was IF 8/16. Energy has been up and down, sleep has been a little weird (insomnia, night sweats.)
I have been forgetting stuff like mid sentence too lol, but I feel like that brain fog is starting to lift.


The verdict: 7 days to get back to nutritional ketosis

After 1 week back on keto (see above for further detail) I tested my blood today and am at 1.2 mmol/L which appears to be optimum nutritional ketosis. Assuming the Ketomojo device is accurate and I am correct about what these numbers mean, it took 7 days (or less because I just got the device) and I am fat adapted again after about 4 months off.
Those months I had planned on getting back on keto soon so I spent every day like it was my last carb binge and had a field day with some tasty sweets and awesome pizza and f*#(ing Elegant Farmer Apple Pie a la mode omg I will never stop craving that lol. Huge popcorn and Coke at the movies (this is the thing I miss most, why cant popcorn be keto friendly?!?)
I am relatively not hungry, I no longer forget what I was saying mid-sentence (I was feeling pretty dumb this last week, with a cool fog drifting through my brain), and am starting to feel that general keto high that I used to have resulting from knowing my body is doing great things.

(Little Miss Scare-All) #11

A little while back, I went from strict keto for months, then went into a deep depression and ate whatever tf I felt like for a couple months. Ended up feeling like utter crap and knew I had to get back to the keto woe. It took me about 3 months to get into noticeable fat adaptation. One day I literally woke up and felt like I could just go go go, and could go very long periods of time without needing to eat.

I lift and do HIIT, and my workout output got amazing just overnight after about 3 months of pretty perfect 20g or less of total carbs. Didnt measure any other macro. I drop fat quickly as long as that 20g is adhered to. I just continue to make an effort to try to eat more fat than protein, but it doesnt always work out like that, and I still steadily lose fat and gain lean muscle.

So, everyone’s different, but 3 months is my personal experience of noticeable body change and energy change.