Was doing great - then ran out of gas and brainpower. Help!


Hi! I’m having trouble with energy levels and brain fog, so I’d really appreciate some advice from you lovely people.

First, some background. I’m 59. Had chronic fatigue syndrome for decades then got my energy back by switching to an all natural, low carb, paleo diet 7 years ago. Over the 2 years (especially after a sickness and menopause with sometimes severe hot flashes) my energy level hasn’t been great. Decided to try keto mainly for better long-term brain and body function. Don’t need to lose more than a couple kilos, so that’s not an issue.

I started keto almost a month ago. I measure using Ketomojo and have consistantly been at 1.1 or above. For 2 ½ weeks, I had almost o keto flu (which I though made sense, because I wasn’t reducing carbs all that much).

For the last week, I’ve experienced extreme low energy and brain fog (as in, cannot function at all) some of the time. Was unfit to work today. I’ve also been super sensitive to smells, noises, etc.

I’ve been extra careful to drink lots, been adding tons of salt, been supplementing magnesium. Also, after reading posts in this forum, I’ve switched to just keeping carbs under 20 net carbs, keeping fat high and eating protein till I’m full (was limiting protein before).

I thought it could be a potassium deficiency since I wasn’t supplementing or paying particular attention to levels, but I haven’t had one cramp, headache, stomach upset.

I’ve ordered a potassium supplement and in the meantime and making sure to get lots of potassium from food. But I’m not at all sure that it’s the cause. It does seem to help somewhat, but can I be so low on potassium and not suffer traditional symptoms of low potassium?

Any advice? I really can’t function at this low-energy / foggy brain level.


(Bunny) #2

Your body is still dependent on carbohydrates so you will feel tired (basically the keto flu) until your mitochondria decide they are going to be burning fat for fuel and there will be very few carbs to eat.

You may have to just tolerate the low energy (glycogen depletion) for a while, until you fully adapt to eating more dietary fat with time which could take 27 weeks from the day you started to reap the full benefits; that is when your metabolism returns to normal as if you never where on ketogenic diet?

That still amazes me how that works.

(Marianne) #3

Hmmm, I’m sorry this has been your experience. Looking at what you are doing, there isn’t really anything that sticks out to me as a concern.

Not knowing everything, all I can do it give the same advice I give everyone - eat three good meals a day, even if you don’t want to, with sufficient quantities and fat, keep the carbs under 20, don’t snack, eat clean foods, and don’t try fasting for now. Do this for 2-3 weeks until your body adjusts to the switch metabolically.

Generally speaking, I felt great right from the beginning, however, I would get very tired with just minimal exertion. Even stuff like cleaning, etc., I would get out of breath and maybe sit down for a bit (I was very out of shape and used to doing nothing before then). It didn’t affect my work because I had a desk job and was sitting most of the time. Sustained energy didn’t come until about 4.5 months in after I became fat adapted.

Good luck; please hang in there.


But do people who were low carb to begin with also experience extreme carb flu?

Also, if it were carb flu, wouldn’t I have got it earlier, not 3 weeks in?



been there and it is wild for each person.

toxins leaving the body at it’s speed…not any other person’ timeline.

So eat as needed. More exhausted ya are…eat up :slight_smile:
I hit it also. Like 9 months into my zero carb eating I got so tired…huh? I was eating less. Just not needing food but needing food. I just didn’t listen.

I ate a bit more each meal. 2 meals per day. I put in some ‘snacks’ eating which I didn’t require per my mind but I said, what the heck, I ain’t hungry but I will eat a few cubes of cheddar and a few slices of salami…….I improved a lot on my exhaustion.

hope that makes a bit of sense and take what ya will LOL we are all so diff. that what worked for me might not be you but I pass it on anyway.

and remember ketones are gonna happen on keto plan…your macros will be taken care of if you eat :slight_smile: Just eat a bit more and I think truly you will be ok…a lot of us go thru this at different times in our journey.

(Marianne) #6

I agree.

I think from a lot of our previous “dieting” experience and mentality, we can sometimes be “afraid” or “guilty” about eating more or eating when we aren’t “supposed to” (like to break a fast early, or eat before your OMAD time has been reached, etc.). Now if I am hungry and it doesn’t go away, or I feel “off” energy-wise, I eat something to fuel myself - like a chunk of pepperoni, hard boiled egg, cheese, etc. I feel better and it doesn’t seem to have any negative consequence concerning my weight loss.


I basically have for the last few days already been putting into practice what you suggested:

Blockquote eat three good meals a day, even if you don’t want to, with sufficient quantities and fat, keep the carbs under 20, don’t snack, eat clean foods, and don’t try fasting for now.

I will try eating more. Sounds like fun! I am not holding back because of previous dieting experience. Weight gain is never been a major issue with me.

To be clear, the exhaustion is not as a result of exertion. Today I woke up. Felt reasonable well. All I did was get dressed and ready for work and exhaustion hit so hard that I had to call in sick (for my desk job). I was literally so tired and foggy-brained that talking was an effort.

I would love to hear from people who started at paleo and transitioned to keto. Is it normal in these circumstances to get such bad keto flu?

(Michael - Don't expect miracles and you won't be disappointed.) #8

Without numbers, ‘low carb’ could mean anything. You claim you’re getting 1.1 and above on your Ketomojo. How often do you measure? Do you measure multiple times per day? If ‘low carb’ really means ‘not low enough’ you could be in and out of ketosis which is going to prolong carb withdrawal symptoms and slow fat adaptation or even prevent it occurring. If you’ve only recently started to consume sub-20 grams of carbs per day, that could take some time to burn out glucose and glycogen stores if you don’t stay consistently sub-20 grams of carbs. Some folks have to go below 20 grams due to insulin resistance. Chronic fatigue syndrome is certainly going to cause complications, even if it seemed to be under control on paleo. If you’re insulin resistant, the fatigue and dullness/confusion is probably exacerbated because you’ve cut down on carbs but you’re not yet able to utilize ketones and fat for energy. Double whammy. The good news is it will pass. The bad news is maybe not for a while.

(Joey) #9

You raise a really sound question. Never having been on paleo - just low-carb keto - I can’t speak from personal experience of transitioning from one to the other. But in rereading your original post, I’m wondering if you could expand on why you decided to take on “keto” (from paleo) since it sounds like you were doing fairly well at that point - especially from your original pre-paleo condition of chronic fatigue?

I certainly don’t want to discourage you from staying on the keto course for now. But it’s worth evaluating whether your original goals when going from paleo-to-keto were realistic and how long you want to have such a miserable experience with renewed fatigue?

(Rebecca ) #10

Perhaps you are coming down with an actual virus?


Hi amwassil,

I wasn’t tracking before, so I don’t know how low carb I was, but compared to a person eating SAD, I was waayyy lower. But some days less than others.

I don’t measure ketones multiple times every day, but I have measured multiple times some days (including the day I had the worst fatigue). Was between 1.1 and 1.9. In 3 1/2 weeks never measured below 1.1.

At the moment, I am staying strickly below 20 gm. I don’t have insulin resistance, so that’s not an issue.

Part of my problem reading articles / forum posts is that they relate to people who are starting from SAD, have insulin resistance, and need to lose a lot of weight. I’ve got 99 problems, but insulin resistance ain’t one. :grinning:

My gut feeling is that something is out of balance, and if I can’t figure it out, I’m going to have to bail on the attempt to go keto.


Menopause has kinda kicked my ass. I know that some people get rid of hot flashes by going keto (and many don’t), but that wasn’t the main reason. I started to creep up in weight and have cravings since menopause, which I’ve never had in my life. Keto has cut the cravings, so that’s good. Managed to get the weight and cravings somewhat under control before keto, but keto took away the cravings entirely.

In additiona, a lot of people in my family have had dementia - (although at 90+). Brain has been fuzzier at times since menopause. I wanted that clear keto brain. BTW, I had one day about a week or two in when my brain was super focused.

What I’d like to do once I’m keto adapted is cycle in and out of keto. Chris Kresser, who I consider a reliable source, and others do that.


HI Rebecca,

Doesn’t feel like a virus.

(Bob M) #14

How does one do this?


Hey Bob,

One method is outlined in this interview - https://www.youtube.com/watch?v=_ADaGIyi2Qs

(Bob M) #16

Any transcript? I don’t have time for videos. Sorry.


Yup. Here it is - https://chriskresser.com/your-guide-to-keto-fasting-with-joseph-mercola/

(Bob M) #18

I’m not sure he’s actually out of ketosis. He’s fasting then eating a ton on his refeed days, but eating about 150 grams of carbs on those days. This is after one fasting day and then one “keto” fasting day. My guess is that he likely never gets out of ketosis, even with 150 grams of carbs.

(Joey) #19

@ctviggen FYI, for future reference: there’s an auto-transcript feature on Youtube.

Click on the three little dots ( . . . ) under the video box on the right side to get a (reasonable) transcript scrolled on screen. I find this is a great way to dash through videos where the visuals aren’t so important.


wake up and getting ready for work…….I didn’t see any food eaten :slight_smile:

you might be one who requires food upon rising…try it out, never know
experimenting on ourselves is key. little changes could be monster success.