The keto flu: symptoms and relief

Many people (not everyone!) who start a low carb diet experience what’s called the “keto flu” or the “induction flu” in the first few days while the body is adapting to burning ketones instead of glucose. The basic symptoms are:

  • headaches
  • nausea
  • upset stomach
  • Lack of mental clarity (brain fog)
  • sleepiness
  • fatigue

It’s called the “keto flu” for a reason: you feel sick. I’ve gone through it and it wasn’t a pleasant experience. Fortunately it only lasted 4 days (2 of them were pretty bad) but then suddenly I woke up feeling much better, less hungry and my energy level was really high and consistent throughout the day! While at one point (or three or four) I thought to myself: “what the serious F am I doing? I’m going to die!”  but I plowed through it and when it was over I didn’t regret a thing because what I gained mentally and physically was 100% worth it.

How long will the keto flu last?

It depends. Some people don’t experience any symptoms at all, but some suffer anywhere from a day to a week. Rare cases up to two weeks. Everybody’s bodies are different and some people handle switching over better than others. You might consider starting keto on a weekend or sometime when you’re able to get good rest deal with the symptoms.

For those of you that are going through the keto flu, don’t give up! I know you feel like it’s never going to get better but stick with it and you´ll be so happy you did! I’m telling you, waking up refreshed for the first time in years, not getting the afternoon “blah” feeling and stuffing my face with carbs to try to boost my energy is the best side effect of the lchf/keto diet I’ve experienced. Okay, losing weight while eating good food, feeling full and satisfied is great too ;)

So what can be done to lessen the symptoms?

First you have to understand why your body is reacting this way. Your body’s been burning glucose for energy so it’s basically full of enzymes that are waiting to deal with the carbs you eat (and probably store them as fat) reference. But now the body needs to make new enzymes that burn fat for fuel instead of carbs, and the transition period causes your flu-like symptoms. There are some things you can do to lessen the symptoms of the keto flu and to make it go away sooner (to force the body to transition sooner) Ok, let’s get to the good part – what to do:

  • First of all – you’re probably dehydrated. Drink PLENTY of water while you’re on the keto diet. And then some more.
  • Watch your electrolytes. When the body is getting rid of excess insulin from your former carb-crazy diet you´ll lose lots of fluids that have been retained in your body. This causes the rapid weight loss most people see in their first few days of ketosis, it’s mostly water, sorry. When you lose all the retained water you also lose electrolytes like sodium, magnesium and potassium. When you’re lacking them you´ll feel like crap so when you’re feeling really ill on the keto flu try things like chicken/beef broth and look for foods rich in these minerals. Take a multi-vitamin and a multi-mineral. I’ve heard good things about
  • Eat more fat – Yup, load up. Butter everything, bacon everything, eat fatty meats and put heavy cream in your coffee. This will force your body to hurry up the transition. You´ll think this is crazy and think you´ll never get skinny eating this way, but you will.
  • Don’t eat too much protein – The body can transform protein into glucose so if you eat too much of it in the first days it will slow down the transition. Go for fatty meat and cheese if you can, add fat to protein shakes etc. The first instinct when you’re on a diet might be to nibble on a chicken breast to lose weight. Don’t do that unless it’s smothered in cheese, wrapped with bacon and has some mayo on the side :)

tl;dr: Drink water, replenish electrolytes (sodium, magnesium, potassium) with food and supplements, drink broth, eat fat and not too much protein.

I really hope this helps. I know it helped me getting over the worst of the dreaded keto flu.

{ 141 comments… add one }
  • fred May 23, 2012, 7:55 am

    Thanks for your article, i have the flu right now and will try out your suggestions.
    Greetings to iceland.

  • Daniel June 2, 2012, 11:13 pm

    Thanks, this is my second time doing keto. I hear it’s supposed to be easier the second time around, not so far. I’ve felt hypnotised all day today with a horrid headache.

  • Chris June 14, 2012, 6:43 am

    Also my second time. Never got the flu before. I feel like death. I just keep reminding myself how great I’ll feel once I’m in ketosis!

    • Lilly June 14, 2012, 9:21 am

      Hang in there Chris, I know it’s rough :) You know it´ll be worth it.

    • laurie July 29, 2014, 5:09 pm

      try getting the keto stix (available at Walgreens and Amazon like $11.00 for 50. They are a pee stick to test your dietary ketosis levels…just a thought.
      Also check out the pod casts of Vinnie Tortoruch-have a lot of great information.

  • Mary July 10, 2012, 8:07 pm

    I began this low-carb “diet”/life style about 3 days ago and I feel like I have a really bad flu. I have not totally eliminated carbs I am just (seriously) limiting the amount I eat… I try to limit fats (cholesterol) as well. I am having a great deal of difficulty focusing and recalling simple things. Will I get over this flu like feeling with limiting carb intake? I was a carb addict!! I did not realize how bad until the past 3 days. Should I keep this up? I have not lost any weight!

    • Lilly July 10, 2012, 9:10 pm

      Hey Mary :) Keep it up! I know it feels awful and like it´ll never go away but trust me, it will. And when it does you´ll feel soooo much better. The way I do low carb is 65% fat, 30% protein and 5% carbs (mostly from green veggies). Are you doing a high protein diet then? In my opinion the fat is essential to feeling full and giving the body enough energy on a low carb diet, too much protein and you´ll put a strain on your kidneys. I was a carb addict too, I didn’t realize but my diet must have been something like 85% carbs before, no wonder we feel like crap while switching over :)

      • Roy December 31, 2012, 6:44 pm

        Lilly – Just wondering, with the 65/30/5 diet, do you limit total calories as well? I mean have you monitored your daily calorie intake – is it low to support any weight loss that you may have seen?

        • Lilja January 3, 2013, 1:06 pm

          Sorry for the late reply. I don’t limit calories much but I do think about that I eat and make sure I stop when I’m full and only eat when I’m hungry, not our of boredom etc. I have monitored it and sometimes use (with the keto addon – check out caveman keto: ) to see if I’m on track. I’m usually pretty spot on with my macros and always amazed at how few calories I’m eating without even trying. I’ve been on calorie restrictive diets before and felt miserable. I’m actually trying right now (you know, new years and all) to log my food on MyfitnessPal and lo and behold, I’ve been adding a few too many calories by putting coconut oil and cream in my coffee all day long. So now I only do that with the first cup of the day :) Sneaky calories!

    • Farrah March 29, 2014, 7:26 pm

      You can’t limit your fat intake AND your carb intake at the same time. If you do this, you will go into what is known as rabbit starvation, which is essentially protein poisoning. The ketosis diet calls for the majority of your calories to be fat, then protein and leafy greens second, and carbs third or none at all. I hope this helps, and I hope you feel better. I’m feeling the start of my “flu” today. And, I hope it doesn’t last for much longer as it’s pretty awful.

  • Ann July 13, 2012, 6:42 pm

    Good information! I started 4 days ago and have been pretty heavy on the protein. I’ll cut back on that for the next couple of days. I’ve had a mild headache for 3 days and my concentration is nil. Hopefully all will be back to “normal” by Monday!

  • Amy August 12, 2012, 4:30 pm

    I am on my sixth day of LCHF and feeling a few things, first a slight bit of anxiety, heart a little racy, hypersensitivity to light and sound, a little euphoria, and nauseated. I’m guessing I must be doing something right to feel this way. Any additional advice you may have and is this normal?

  • Lauren September 7, 2012, 5:57 pm

    You know, keto flu sounds a lot like morning sickness…

  • kirsty October 3, 2012, 8:50 pm

    I started the primal diet about two weeks ago and felt great until a couple of days ago. It is such a relief to read that what I am experiencing is normal. I have had a terrible headache, panic attacks and fatigue. I was wondering if it is normal to feel feverish in the night. I have been waking up with the sweats and a high temperature but feeling cold. Has anyone else had this?

    • Lava April 23, 2015, 8:43 pm

      Hey Kristy,

      I am on my 8th day of Atkins induction and for the past few days I have experienced exactly what you stated. I feel fatigue and been sweating my ass off while sleeping and worst thing for me was the cold body parts. My hands and feet seem to be freezing cold most of the time and its driving me mad and making me so uncomfortable. I was wondering if this has passed you or how you dealt with it? Thanks x Lava

  • Dimitriy October 14, 2012, 7:47 pm

    Help! I’m with a very sick stomach right now. It started on the 6th day of the lchf and it’s second day already. My stool is mostly liquid (almost like water) and I have terrible pains in the stomach. Mind control is actually ok. Just wondering if it can be keto flu or it’s something else I should worry about?

    • Lilly October 14, 2012, 8:02 pm

      I wish I could help you, Dimitriy. My husband got upset stomach the second time he did keto and eventually it went away. But is truly sucked and I do think it’s related to going into ketosis. You could try asking on a low carb forum or the keto subreddit ( ), lots of experienced people talk about keto there and many have gone through the keto flu. At least keep your electrolytes and fluids up and if all fails try asking a doctor.

  • rad November 20, 2012, 1:43 pm

    Ever since I started my Atkins diet,I was looking for some info which was beyond just the atkins website and the book itself.I have been following the atkins for the past 3 weeks and since I have to lose another 50lbs I thought of sticking to induction for little longer.I would greatly appreciate it if you could guide and help me and let me know if I have been doing it right.If it is ok with you,I wish to share my diet and use you expert comments to speed up my weightloss.So far I have just lost about 6 kgs and this is my 3 rd week infact just about to start with 4th.
    This is the diet I have been following:
    2 egg omelette + 15 ml rapeseed oil + 100 grams lettuce + 1/2 tbsp mayo
    120 grams chicken(frozen) + 15 ml rapeseed oil + 1 cup broccoli(frozen) + 50 grams lettuce
    2 egg omelette + 15 ml rapeseed oil + 1/4 cup onions + 1/2 cup mushroom + 50 grams lettuce
    100 grams chicken(frozen) + 15 ml rapeseed oil + 1/4 cup bell pepper + 1/4 cup onions
    IN addition to this I drink 1 cup decaf tea using 1 tea bag with 30 ml single cream and add 1 sweetex.
    Initially I also used to consume 3 0z of cheddar cheese but stopped it after reading many post saying it stalls weight loss.
    Drink around 2-3 ltrs of water every day
    Please help

    • Tracey February 1, 2015, 12:47 pm

      Oh God, get off the rapeseed/canola oil! That stuff will kill you!! Use butter, ghee, other animal fat, coconut oil and maybe a little olive oil. Don’t be afraid of fat, it’s good for you.

  • Simone November 29, 2012, 8:03 pm

    Ugh I’m so nauesous, the thought of eating fat is repellant and not appealing! But I will keep eating it. I will prevail!

    • Danny November 11, 2013, 6:41 pm

      Do you remember how long it took you to get over the nausea?

      • Lilja December 11, 2013, 9:24 am

        I’m terribly late to reply, but the nausea lasted about a week, maybe a little more. It’s worse if you don’t eat.

  • cookiecate January 4, 2013, 10:46 am

    Thank you for making this so clear and understandable. I wish my Atkins book had helped as much. Thank you.

  • Margaret Goodwyn January 6, 2013, 6:51 pm

    I have been on the ketogenic diet for four days. I’m usually rubbish at diets and my willpower is not so good but I am managing. The only issue is the keto flu, it is horrid. I have got that warm funny feeling in my throat and nose like the onset of flu. I have also got muscle aches and lethargy. I feel freezing cold but I have clearly got a temperature. I am hoping this will pass soon because I really can’t be doing with these symptoms they make me feel so yuk.

    Anyone any ideas if this sounds like keto flu or an unfortunate coincidence?

    Many Thanks

    • Lilja January 6, 2013, 11:03 pm

      Hi Margaret. It does sounds like you might have a touch of real flu, I hope not though. I never had a temperature during my keto flu days. I will say that four days is awesome, well done! The worst is almost over and I sincerely hope you´ll wake up tomorrow feeling better and can start enjoying ketosis and losing weight :)

  • Loula January 31, 2013, 9:16 pm

    Thank you for posting this topic! I’m only on day one and after having eggs with turkey bacon for breakfast, I can barely stay awake at work! I usually have oatmeal for breakfast, which I know now is loaded with carbs. What about all the cholesterol in fat, eggs, cheese, etc.? We’ve been taught that’s not good for our heart.
    I just read on another website that eating fequently in the beginning stages of the ketogenic diet helps minimize symptoms.
    Thanks again,

  • Lila February 1, 2013, 12:18 am

    Hi every one! I started the LCHF diet about nine days ago. Will this keto-flu ever go away? On some days it´s not so bad, but some are just terrible. I feel dizzy, very tired, my muscles feel weak, I´m nauseous, stomach feels weird, brain fog (I can´t think clearly) I can´t workout (I do interval training 4 x a week), I feel very hungry every 3 to 4 hours (do I need to eat more fat? (afraid I will gain weight if I eat too much fat. It´s weird for me to eat so much fat) or is that the normal amount of hours without eating? Can´t tell any more since before I would just snack all the time). My carb intake must be less than 50 grs. I just feel sick overall. Is this normal? I keep wondering if I´m making a mistake or I´m not doing it right or maybe this diet is not for me. I´m not over weight, but I do want a less % of body fat and have a healthy lean body (with no junk, no grains). I think my bodyfat percentage is 24% and I want it to go down a bit more. I´m also doing it because I had terrible cravings and there was a point where I was starting to binge (sugar most of the time) and that was when I said “wow, something is not right here”. So yes, now I have no cravings at all, at least I can eat until I´m full and not worry about calories or portions, I just listen to my body and trust it. I do not snack anymore, but I do eat like 5 times a day because I still get very hungry every 3 to 4 hours. Is hunger also a symptom of carb-withdrawl? I´m so happy I can see sweets, and baked goodies and have no desire to have them at all. That is a big deal for me. This a huge reason for me to stick to this diet, but what if I´m always going to feel crapy? Maybe be it´s too soon to tell, but you mention a week or two. So I guess I will wait. I just recently moved to Canada (I am from Mexico) and the food here is soooo diferent. I think I was even starting to gain weight, so this is when I started counting calories, limiting my portions, feeling very deprived all the time and still be hungry with huge cravings It was hell and not working! This did not happen in Mexico. In Mexico I could eat all I wanted until I felt full, satisfied, did not gain any weight at all and almost had no cravings (some sugar cravings since my diet did include the so called “healthy” carbs and some sweets now and then). I was happy :) This is why I decided to do some research, found about this diet and decided to give it a try because the rest was not working. My clothes didn´t fit anymore either because I was bloated all the time or I had gained weight. Can´t really tell (I do not have a scale). My clothes still doesn´t fit, but I guess I still have to wait for my body to loose the excess water, start burning fat and get back to normal with this LCHF diet. I also want all the other health benefits that everybody is talking about. Any thoughts, comments, tips or ideas for me?? Thanks a lot!

  • Josh February 1, 2013, 5:38 am

    OMG, and thank you so much for this article. I’m in the third day of keto and I could of swore I was dying. I was convinced this wasn’t normal. I’ve read that you feel like crap but not like it’s your last day alive. This gives me the strength to keep going.

    • Gale July 6, 2015, 9:07 pm

      LoL, I’m sorry, but this made me laugh way to hard. I’m feeling this at the moment so was glad to see this comment.
      Day 8 LCHF

      • Chels September 22, 2015, 7:53 am

        Omg thanks for this site and blog!! I hadn’t even finished reading all the comments before I hopped in my car and sped to Walmart before it closed to pick up potassium and broth

  • fatchickfromnola March 10, 2013, 6:30 pm

    Holy smokes! This is only day two and I want to give up. I was sick all last night and didnt get any valuable sleep. I am not hungry at all today… OH and it is only day two. I finally made myself eat something at 130pm and it isnt sitting well with me. I am glad to see your blog and will try and hold on.

  • BigEvil March 22, 2013, 12:55 am

    Do you go through the keto flu again if you break ketosis even briefly?

    • Lilja March 22, 2013, 8:47 am

      If it’s only briefly I don’t think you´ll get a full blown keto flu, maybe a headache or feel a little blahh for a couple of days.

      • Brenda April 25, 2013, 4:16 am

        yes you get the keto flu every single time you break the diet. And for me it is just as bad every single time.

        • ALEXANDRE CASTRO July 30, 2014, 1:42 pm

          It really happens to me everytime a break the diet… and the same intensity !!

    • sylvia king August 30, 2013, 3:02 am

      If you break ketosis or cheat while trying to get into ketosis you will have to go through another 2 – 4 weeks feeling crappy again.
      Do not cheat. Stick it out for at least 8 weeks. Once you have keto adapted it is much easier to stick to it.

  • Robert March 28, 2013, 2:28 am

    The type of magnesium can be important. A lot causes diarrhea. Magnesium glycinate seems to work for me.

  • Patrick April 2, 2013, 6:46 am

    I feel like this right now, minus the headaches. Woke up last night hugging the toilet, because i felt like puking. I’m experiencing nausea, acute upset stomach, and of course fog mind and tiredness.

    • ALEXANDRE CASTRO July 30, 2014, 1:46 pm

      Many of these symptoms I believe are due to “die off” syndrome ( Fungus/yeast just die with this diet ) which is nothing more than symptoms related to toxic stuff released by dead fungus.

  • Vanessa April 5, 2013, 6:29 am

    I have been on ketos for 2 weeks and my flu is the worst its ever been. In addition I had overcome panic attacks years ago and last night I had one for the first time in years. My head is light and I have a raging temp. Dam Dr put me on poisonous meds and I thought this is playing havoc with my Nuro cells. I am not going to give up. My kept sticks encourage me so much. i am on cortisone I hope this wont affect me.

  • JoyceS April 19, 2013, 1:12 am

    I’m on my 6th day and experiencing Keto Flu. For mr, it reminds me of morning sickness. Always queasy with a very dry mouth. Twice I woke with major sweats during the night. I don’t believe I had a temp either time. I did not get the chills. I feel somewhat less queasy once in a while. I have been trying to load up on fat and water, but forgot about cutting down on protein. I’ll try to do better tomorrow. Regardless of how I’m feeling, I’m not craving anything. My willpower seems strong. I was a very high carb eater prior to this diet. I sure hope I get over this feeling sooner than later.

    • Lilja April 19, 2013, 8:27 am

      6th day? I’d say you’re unlucky, JoyceS but I admire your willpower. I’m sure it´ll be over very soon and you´ll feel fantastic :)

  • Olöf Melkorka April 30, 2013, 4:58 pm

    Hi all, I´ve been on low carb now for abt 3 weeks (slipped 3x). I have been enormously tired. Very irritable. I have some change in my skin color on some parts of my body where skin meets skin. I do not feel really hungry but I get mental cravings.
    My dr. does not oppose to this foodplan, neither does my dietist.
    I have been a jojo eater for some 30 years, gaining weight rapidly over the years.
    I´ll guess I will continue, one day at a time, and hope this flu will go away.

  • Lola May 1, 2013, 4:29 pm

    OMG – I just stumbled on this info and the timing couldn’t have been better. I’m on day 3 and have all these symptoms. Interesting information about increasing fat intake! It goes against everything I’ve ever known. I’m not giving in though. I’m sticking with it! What do you recommend for protein to fat ratio?

    • Lilja May 1, 2013, 4:31 pm

      I do 65% fat, 30% protein and 5% carbs. It’s % of calories.

  • Matthew Mitchell May 4, 2013, 7:48 pm

    What about reducing carbs more slowly? Going from very high carb to very low carb might be too much of a shock. I’ve reduced carbohydrates over many months of being slowly convinced that carbohydrates are likely a cause of problems for me.

    About five days ago I went from having carbs from vegetables and fruit, to having carbs only from low-carb vegetables (And negligible amounts from cheese). That small change has made quite some difference. My eczema seems to be improved (probably the fructose in fruit causing inflammation?); I don’t have the reactive hypoglycaemia after eating fruit or starches vegetables; but I do feel quite generally drowsy and exercise has been harder than usual. I don’t have other flu-type symptoms.

    I’ll probably go for a long walk tomorrow or the next and see how I feel.

  • Christy Scott May 7, 2013, 4:22 am

    I have been doing low carb (between 20 and 35) for about 25 days. I didn’t start to get headaches until around a week ago. Every day I have a headache. It’s the worst today. I feel sluggish. I’m wondering if I’ll ever get over this. Most people are saying that it lasts only a few days. Maybe it’s my age (55), or the fact that I was prediabetic when I started this.

    • sylvia August 30, 2013, 3:08 am

      Make sure you are getting enough salt. Try drinking broth or eating pickles.
      Also make sure you have enough potassium. Eat more avocado and tomato.
      I go to Costco and buy Eco Drink which is a sugar free multivitamin powder you put into water. It has potassium and other electrolytes.
      You may not be getting enough of these and this makes one feel awful, headaches, fatigue, foggy brain etc.

  • Nicky May 9, 2013, 12:58 am

    Hi – I have a question, I’m on day 6 and since yesterday have been suffering the most horrendous stomach cramps (nothing to do with other female ailments we have to deal with). Is this normal? Admittedly the first 2 days did involve 1 piece of bread so technically may only be day 4. Thanks

  • veronica May 23, 2013, 10:23 am


    I have been on LCHF diet for 5 days and since yesterday I have all symptoms keto-flu.I feel awful and from yesterday I have not eaten as I cant face any food at the moment.
    I eat a lot of cheese and not sure if is good to eat as much as I do.
    Is there any food that I should eat to help me with this keto-flu?

  • Belle May 23, 2013, 5:10 pm

    The 8th day into my low carb diet is when my horrible stomach pain began. Only other symptom is fatigue. This is day 11 and have had upset stomach now and then since day 8. Do you think it’s the keto flu?

  • Dom June 27, 2013, 4:17 pm

    Having done paleo for a number of years with success, I started adding more and more starches (Sweet potatoes and potatos) to my diet to put on weight for athletic reasons. This eventually led to a slippery slope of me eating all kinds of crap. Four days ago i decided to clear it up and go keto. Wow, I am really suffering. Nausea, thumping headache. Basically like a really bad hangover. It was so bad today I caved and ate fries and a coke (neither of which i would normally eat anyway). The headache was gone with twenty minites allowing me to get some work done but the other symtoms remain. I’m soooo thirsty! Having read this I’ve definately had too much protein. Have i just extended the misery setting myself back like this? I didn’t notice any symptoms at all the first time i cut out carbs so Im quite puzzled by this.

  • pat August 15, 2013, 4:00 am

    Second day of strict keto, second time doing this diet, first keto flu. Headache from hell. Tired. Brain fog. Absolutely useless at work. Cranky and depressed. Thinking about bailing for some dairy queen to get through the night at work. All I need is sleep, but I screwed up all day because of this and have to fix it tonight. Can’t even concentrate. But knowing you guys all suffered too helps. Ain’t gonna quit, cause then I have to do this again. Yuck.

  • Bob Atkins August 18, 2013, 3:49 am

    It’s uncanny- but comforting to read exactly what im going through. The headache (not a typical stress headaches, something different). Feel like im walking in water, I feel so warn down. I’m glad to hear this is temporarily, ive been doing this diet for about 2 weeks, but only last 4 days been really following it to the letter- and I got the A flu big time. I just laid down, at 5pm, and slept till 8:30 something I never do, especially on a Saturday. I have to say exercise helps, even a good 1 hr power walk, you can feel yourself breaking through the wall- I have a feeling exercise will help getting through the flu faster- will try it and see what happens.

  • Bob August 24, 2013, 3:16 am

    Im about 10 days to 2 weeks on atkins ( I lost track exactly), and I am doing great. I hit the wall about a week ago, (flu), it was very annoying and I knew it had something to do with the diet, because I never felt that particular way or crummy before. I came online, and discovered it’s know characteristic of the diet. I have to say, with no carbs- im surprised where my energy is coming from and how much of it I have. I generally workout in the evening, about 1-2 hours treadmill, lifting and elliptical machine, then afterwards im so pumped I walk cause I cant settle down- I see a profound increase in output in the gym, and I eat practically nothing, and what I do eat is fatty meats, cheese certain vegetables roma tomato, broccoli, cucumber- quit all fruits, and am drinking water like crazy can’t seem to get enough. I see myself shrinking daily. I think the name of the game is exercise with Atkins, regardless what type of exercise you do- try to do just a little bit more, once you get moving you’ll be astonished how much energy is waiting to be released.

  • Tammy December 1, 2013, 1:18 pm

    I have been debating on this for a very long time. I am a 41 year old and have struggled with my weight since I was a teenager. I have gone through this, but no longer than 3 days at a time, because I immediately felt the “flu” symptoms. I currently work 7 days a week in the automobile industry, so it is very difficult to do this on the weekend. But after reading these posts, I am 100% convinced I need to do this. I have all the symptoms of a carb addict, and I can tell, because I constantly feel bloated and constantly crave carbs.
    Today will be a new day for me, I have not eaten anything today but brought some tuna to work, and that is what I will eat. I am convinced that I will get through this…thank you!

  • cara December 6, 2013, 3:30 pm

    I am on day 3 now and the flu finally hit. I feel absolutely horrible. I was definitely a carb loader before. Every single one of my meals consisted of high carbs so I am not sure if that is what is making it so much worse but YUCK. It feels nasty. I am tired, feel VERY nauseaus, and irritable. I am holding strong but it for sure is not one of the most fun times in my life haha!

    • Lilja December 11, 2013, 9:23 am

      I hope you’re still in it :)

  • Melissa January 4, 2014, 3:15 am

    Before I started Atkins on Jan. 1, most of my diet was veggies and beans. I’m at day 3 and I don’t feel anything. I actually feel great. Does this mean I will never hit ketosis?

    • Lilja January 6, 2014, 8:47 am

      No, probably just means you’re lucky :) You can buy keto urine strips to check if you’re in ketosis.

      • Dawn January 8, 2014, 11:08 pm

        On my 9th day of induction. I went thru the “flu” on day 2, and by day 4 felt really good. I have lost 3 pounds so far, but I did start my WOE(way of eating) a week before my TOM(Time of month) so that wasn’t smart. haha I do have a headache today, and I think I have been eating to much protein compared to fat, so I am upping my fat intake. We will see what happens. Good luck to those going thru the “flu”. Hang in there it gets better. :)

  • bonnie January 11, 2014, 9:27 pm

    This is my 6th day and not realizing the signs until today ,I have keto flu…feels like crap, but i know it will get better because this is second time for me doing this, however i do think i`m eating too much protein . I will continue because i have to get this weight off.

  • Justin January 15, 2014, 9:58 pm

    Could you elaborate on exactly what is “too much” protein? For a 170 lb male for example, 250-300g is fine but anything over that is the breaking point. Or how many grams per lb is the maximum intake on a ketogenic diet, for example, greater than 1.5 grams per pound of body weight is too much for this diet. I’d greatly appreciate a response! Thanks

    • Lilja January 15, 2014, 10:00 pm

      Hi Justin. I really recommend this keto calculator where you can enter your personal details and get a great breakdown of what your macros should be:

  • Kayla January 17, 2014, 6:00 pm

    Current financial circumstances have put me on a low/no carb diet here lately without my meaning to. With hypoglycemia- I thought that was the soul reason for my sickness but even fresh fruit hasn’t helped lately. Thanks to your article I realize I am going through this (for me) debilitating flu because I eat very few carbs or fats… Mainly fruit and protein (I guess not enough protein to bring me out of the slump! Lol). But I’m considering sticking with it since I’m already in the throes. Thanks for this information.

  • Jenny January 21, 2014, 3:09 am

    Interesting reading all the variations. I’m into my third week of grain and sugar free as much as possible following LCHF. About 10 days ago I started with a sore throat and nose. Excruciating thirst even though I had saliva, dry scratchy eyes and I felt as if I had a fever, general weakness etc. I’ve stuck with it and tried increasing my electrolytes. I am improving but I felt so bad I seriously considered seeing a doctor. I think I’m eating 30-60g carbs per day and about 50g protein, 100g fat. I’m probably going a bit over on the protein.

    • Lilja January 21, 2014, 10:08 am

      It’s rough. I got dry eyes and skin too when I was starting out but it got better. I notice it more if I forget to drink a lot of water and am low on salt, that also makes me feel tired. If you’re wondering about your protein intake you can try this calculator, I like it a lot:

  • Adriane February 24, 2014, 1:53 am

    Is it normal to have a sort of empty feeling in your stomach even after eating a meal? I am on day 5 of Induction and aside from feeling a bit light headed, this is the only other side effect that I have noticed. For example, I just ate a homemade hamburger wrapped in lettuce with a touch of mustard, a few grape tomatoes, one slice of pickle and a sprinkle of cheese. Despite it filling me up physically, I still have a gnawing feeling in the pit of my stomach. It’s very distracting and slightly uncomfortable. What can I do to ease it a tad?

    • Sedra December 19, 2015, 7:27 pm

      I feel exactly the same ! That weird kind of knawing emptiness, but not hunger related. I felt that perhaps it is me feeling an emotional eating addiction. I feel like perhaps I’ve been eating to fill a void and now here it is to say hi, no carbs to hide behind! I find it a good time to invite more activity into my life, get into the sunshine, swim, walk, enjoy the good things of life and try to swap out that emotional eating pattern for a love of life. Not a great diet suggestion though, and may not change overnight but ….. That’s what I got !

  • Marilyn Robertson March 6, 2014, 2:52 pm

    I am in the flu…….I have started like 3 days ago on this diet. So, it feels just like fibro to me. So, yeah I love water, no problem there, I love meat, no problem there. I also love my eggs, mayo, butter and heavy cream. I just want this to hurry and finish already. I think I will spend the day in bed…with my computer and phone. I am tired and need to sleep some of this off. Will be going off to bed….for now. :-(

  • julie March 22, 2014, 2:01 am

    Hi Marilyn, I have fibro too and am just starting this diet, how are you feeling now? has it helped and I have Me and fibro anyway so this flu sounds easy to me :)

  • nick March 26, 2014, 9:36 am

    did atkins 4 years ago and lost 3 stone in 6 months, felt really good but then suffered TIA, not 100% that it was connected but was scary. Started again recently and so far am suffering chronic diahirreoa periodically and headache, normal?

    • Lilja March 26, 2014, 9:38 am

      I’m not sure, Nick. I’d consult a doctor just in case.

  • J March 26, 2014, 1:58 pm

    I started doing low-carb 6 days ago and I feel like crap. Diarrhea after every meal, I am very fatigued, and my face feels hot. Haven’t actually taken my temperature. All this is legitimately normal?

    I have also been having headaches but those have been happening on and off for weeks (I think tension headaches). I saw where diarrhea, fever, fatigue and headaches is a sign of a serious infection but I don’t know whether to worry or not. All I know is I feel like I have the flu.

    • Lisa October 22, 2015, 7:36 pm

      I have the “hot headache” too. My face and forehead feel hot. I’m 2 days into re-induction after leaving the keto zone during travel. I know it will pass. I just wanted to acknowledge the hot face / hot headache in case anyone else out there feels this way too! :)

  • nick March 28, 2014, 9:09 am

    Thanks Lilja, I should also say that I am currently taking Anexity and blood pressure tabs. it appears that the symptoms, diahirreoa, headache, nausea etc can be attributed to anxiety disorder as well. Suppose the more you worry about it, the more anxious you get. Got docs appointment next week. but still feeling tired.

  • Jay March 31, 2014, 6:39 pm

    I was on this keto die bout 6 weeks until I started feelin horrible. One day after eating, I woke up with a stomach cramp. (I am male, by the way.) I had to work, but I called out because I just couldn’t take it. About a day or two later I decided to have a late dinner of 2 chicken cutlets with some salad around 8:30 pm. I went to bed around 10 and woke up at 1am with extreme cramping in my lower abdomen smack dab in middle just above the pelvis. I stood up all night until about 6:30 am and was furious because I had an interview early in the morning and felt weak and lost. I decided to say screw this and incorporate a little bit more carbs in my diet and slowly it has been getting better. These last 2 days I cheated slightly more and now the opposite happened last night, gassy and a few bouts of diarrhea kept me up all night. I totally dont want to give up, but man there has to be a way for me not to feel this way on important days where I have to work. It was horrible and being that I’ve had gastrointestinal problems before (gallstones, removal of ballbladder and kidney stones) any unusal pain in my stomach that doesnt feel normal, freaks me out!

  • Maggie April 6, 2014, 1:40 pm

    WOW thanks. I had a real hard time with this and it made me turn back
    I will begin again and hold on
    The support on lone is awesome
    Thanks to you and everyone who shares

  • Amie April 10, 2014, 8:44 pm

    I feel like death has taken over. I feel sharp pain in My stomach like knots all over. Is this part of it? My goodness I hope the results are well worth getting through with what I am dealing with.

  • cindy May 3, 2014, 6:15 pm

    I started this diet 5 days ago and I just got this flue..oh boy I feel miserable! But not giving up..already lost 8 pounds so I’m absolutely happy. I’m not quiting! ! Keep it you all :)

  • Gemma Shepherd May 8, 2014, 7:13 am

    Hi, I started the Keto diet for the first time 11 days ago. I’ve had a headache for 2 days and am lethargic but no flu symptoms or brain fog so I think maybe I’m just lucky. I’ve lost 7lbs and have felt ‘on top of the world’ up until the headaches and for that reason, apart from all the other benefits, I’m carrying on. Crazy not to.
    Normal flu can last for weeks and make you feel like pooh, without any benefits apart from recovering so keto flu is like a Christmas flu, you get the bonus at the end!

  • Lacey May 22, 2014, 11:39 am

    First time on a ketogenic diet; nearly a week in. I definitely have the flu. Was super nauseous all night. I wrote it off to nerves at first because my dad is undergoing major surgery tomorrow, but I woke up this morning with a debilitating headache, intense stomach pains and had to put my head in a bucket… and I’ve gained 1.2lbs. I’m not loading on the protein, as I know it can convert. I have been drinking fluids, and I know the body can fluctuate 4lbs a day from water weight alone… so I’m not discouraged. But man, this sucks!

    • Lilja May 22, 2014, 12:19 pm

      Yeah, it really sucks! Hang in there, I’m sure the stress isn’t helping :) Best wishes for your dad.

  • Kasia June 3, 2014, 4:54 pm

    What do you do when you’re going to throw up? Do you eat something carby then or do you just let your body throw up? I’ve tried low carb several times but I always quit when I start throwing up and feeling like I’m about to faint ):

    • Lilja June 3, 2014, 5:02 pm

      It’s a vicious cycle, you’re nauseous but to get rid of the nausea you have to eat, and it’s hard! I suggest bringing a low carb snack anywhere you go, like perhaps some nuts. As soon as you start to feel the nausea, eat something. If you’re actually vomiting I’d consider raising the carb limit a little bit while it blows over. I wouldn’t go overboard and eat a piece of bread or chocolate, but maybe half an apple or some higher carb vegetables along with some good fat. Sorry you feel like crap :(

  • Jill June 19, 2014, 12:33 pm

    This is my 3rd week trying to get into ketosis. My last doctor visit I was only at trace. I’m eating the proper foods, meat, seafood, veggies, fruits and fats. My sweet cravings have all but diminished but I really never had much of these flu symptoms. Maybe a slight headache the first couple days but now the night sweats and hot flashes have come with a vengeance. I am post menopausal for 8 years and without HRT for the last year and was symptom free until now. Any suggestions? Anyone have any experience with DIM supplement?

    • sandra June 30, 2014, 6:26 pm

      Fruit is forbidden in keto diet, and the vegetable intake needs to be at minimum, the best are green vegetables, such as cabbage, lettuce etc.

  • Jane July 29, 2014, 5:44 pm

    I am trying this keno diet for the first time in my life. I’m 50 years old and never been overweight but gradually put on 15 pounds over 4 years. I do bikram yoga and walk. I’ve always eaten lots of carbs: pasta, vegetables, grains and beans. Very little meat. So now that I am week 2 of this diet I am miserable. Jittery and tension in my stomach 24/7. Sleepless after 1 am. Complete loss of energy. I am taking potassium, fish oil and multivitamin supplements and hydrating. The problem is also I fine meat consumption unappetizing. And eggs more than 2x week is all that I can stomach. Is this diet just not suited for some body chemistries?

  • Betsy August 1, 2014, 9:02 pm

    I just radically reduced my carbs to 5% and man do I feel it… like a bad hangover with party heart! Sucks but it’ll pass… I won’t cave! I am moderately in ketosis, it’s been a year since I’ve been disciplined enough to get back in, I was fortunate in maintaining my initial loss of 90lbs and have more to lose… this too shall pass! So glad I found this page, I forgot about broth, it helped (for about a minute) but it’s better than nothing!

  • Marie August 2, 2014, 8:32 am

    This is the third day of my LCHF diet and I’m struggling. Yesterday I only had one meal for breakfast then felt full all day and later very sick. This morning I feel incredibly sick, cold and shaky. I’ve not eaten any form of fat for over 20 years and lived on fruit and vegetables but hardly any carbs. The thought of eating fat makes me feel very sick. I dont really know what to eat to be honest. Not sure I’m doing it right. What veg can I eat? How do I get 65% fat in my diet? I would like to try the greek yogurt option for my breakfast as I like cool refreshing food. Please help someone, as I want to push through this, but not sure I can eat fat after a lifetime of avoiding it!!!

    • Trist November 18, 2014, 3:53 pm

      Avocado? Almond (nuts)?

  • Cassy October 31, 2014, 3:26 am

    I hope this isn’t an inappropriate place to post this, but by day 3 I actually became too ill to continue the diet. (eating when I felt nauseas resulted in, you guessed it, vomiting. The higher the fat content, the worse it was.) I started reintroducing carbs this afternoon and was able to keep them down, but I still feel sick approximately 10 hours later. Anyone have any experience with how long the flu symptoms last after you’re no longer in ketosis?

    P.S. I’m not giving up entirely, just conceding this round.

  • Ali November 13, 2014, 11:24 pm

    It’s due to detox too. The body finally has the opportunity to offload the crud it’s been accumulating for the last few years. Coughs, colds, fevers, rashes, vomiting, diarrhea, etc., are all routes the body uses to offload unwanted matter. It’s having a Spring .clean….

  • Marianamarianagp3 November 14, 2014, 2:30 am

    This is also my second time on a keto diet but Im concerned because I have been on the diet for 4 days now and no signs of the flu… im starting to worry I dont know if my body is not transitioning into a state of ketosis. The first time I did keto I felt like a zombie for the first 3 days, and this time.. nothing. Im sure Im eating all the same stuff as before. Any thoughts?

  • Joyce November 16, 2014, 3:38 pm

    I am in the third day of the flu. I feel like there is no end in sight. My question is about the product “Raspberry Ketone”. Would it help get the body going sooner?

  • Jeane November 27, 2014, 6:16 pm

    Thank you so much for this website!!!
    I’ve had the “flu” for a few days now after a couple of weeks on Keto and was all set to reach for more protein today. Now I will be going for the fat instead! Close call there. :-)) And it’s wonderful to read the encouraging words to stick with it, that this will get better. So glad to hear that!
    Thanks again.

  • Rick December 1, 2014, 5:36 pm

    Started one week before Thanksgiving, blew it out TDay and started back strictly day after TDay(Friday). Felt great on Sunday but had diarrhea multiple times Sunday night once this morning! Is this normal and what should I do, eat nothing but cheese ??? Thanks

  • Paulette January 12, 2015, 5:17 pm

    I have been on this diet since Jan. 2. I have initially dropped 5 lbs. (sure it’s all water) my concern is the exercise. I am an avid runner. (3-4 miles a day, 5 days a week). I have been struggling to complete 3 miles since the diet. Maybe this is attributed to the Keto Flu? Any other runners out there? I want to get back to my exercise levels. Does this get better after you are you are in ketosis?

  • Ankit January 20, 2015, 7:33 am

    Hey guys please tell me that I am eating everything except chapatti, potatoes, groundnut, excluding fat giving things, not much sugar too.. Eating only green vegetables, milk cooked vegetables excluding potatoes and taking certain multi vitamins for vitamin B12 and few more like calcium after consulting my doc.N after my 4th day today I feel same above mentioned symptoms… So am on right path or not. Is there need to change anything..???

    • shilob April 23, 2015, 4:04 pm

      You have to eat high fat….make some fat bombs and some fatty meats. Good luck!!

  • Joy January 29, 2015, 2:38 pm

    I’m on Day 5 of the Atkins low carb diet. Feel faint, nauseous, diarrhea, slight headache, very tired, and cold all the time. Also, my co-workers were worried and checked my blood pressure and it was 148/98 with a pulse of 81. I usually have very low blood pressure. Is this from ketosis?

  • Serena Tagoai February 9, 2015, 2:55 am

    This is my first time. I feel like I’m going to die. I have cut carbs altogether… I’ve had to take days off work, and my pulse is RACING. Last night I had a fever, this feels like crap and I sure hope it works. I am in day 9 arghghghg

  • kim February 27, 2015, 7:10 pm

    Thank you for the in sight…. I am in the middle of full blown, man what have i gotten myself into, keto flu. Luckily it’s been a slow work at week so my fuzzy brain hasn’t had to be overloaded too much and hopefully with your help on this page I can make it through the rest of this “flu” without stressing so much about it.

  • Brooke March 15, 2015, 11:44 pm

    Thank you everyone for your comments! Reading them all has been so helpful. A week ago I was so bad I went to bed for half the day with diarrhea all day long. Then just diarrhea in the morning for five days. Today, one week later I’m in bed all day now worse than that first day with a 101.5 fever. The fever is what really has me wondering. Is a fever also a possible symptom?
    Thank you!

  • shilo b April 23, 2015, 4:02 pm

    I know this sounds weird but I got some coconut oil….it’s in a substance like lard. So I’ve been nauseated since starting so I decided I was eating a lot of protein and not enough fat…..therefore I took a big heaping spoon of coconut oil and ate it. Stomach ache gone within five minutes. It was weird. So can someone tell me is this going to make me fatter. I am consuming g very low carbs. Thanks

  • Mechal May 6, 2015, 1:21 am

    60 hours in. Feel terrible though better than this morning when I woke up at 3a.m. feeling seriously ill. I got back to sleep but felt nauseous all day. The thought of a greasy omelette fried in butter is repulsive. Today I drank broth, and soya sauce to stabilize by electrolytes as I have been peeing constantly for the past two days.

    I think if Atkins has discussed the flu in detail is all his books, significantly fewer people would do this. Based on how I feel I must be the world’s biggest carb addict. Is it worth it to loose 25lbs?

  • MAMA3 May 23, 2015, 1:03 pm

    Hi, I am just starting my 3rd week of Atkins and I feel terrible:( Headaches, nausea, fatigue, the thought of eating makes me feel worse. Is this normal? I thought keto flu was just during the first few days of going low carb?

  • Gale July 6, 2015, 9:39 pm

    Day 8 for me on LCHF, these are my symptoms. Though not Daily but at various times through out the day and sometimes nothing at all for a few hours then it hits.
    Diarrhea hit on days 3-5 and was watery the first day but got better the next two days.
    Weak and tired mostly in the evening, aches & pains in my arm, upper back and neck, but again comes no goes. Blood pressure up in the evening to 140/90. At times out of breath (not to the point I can’t breath but like I just took a brisk walk or a flight of stairs) sitting or standing doing nothing feel nervous many times, mostly when I’m about to get hungry I get almost a panic feeling and sick to my tummy feel. My pulse “feels” like it’s racing, but it’s not (around 66-72). When that happens I feel panic and like death is near.
    I’m so glad these don’t happen constantly and not all together. I can’t wait to feel good again.
    I just wanted to add my Keto flu symptoms so maybe others who have this knows this is “normal” withdrawing symptoms.
    Good luck to us all and stay on track, it will get better (so we’re told :) )

  • catherine September 4, 2015, 5:13 pm

    Hi Lilja,
    thanks for your excellent post ! I had a sore throat started yesterday, I discovered your post before dinner and followed your advice And this morning it was gone !
    I made chicken broth with celery carrot leek thyme salt and cinnamon stick. I let it cooked for 1 hour. I filtered the broth and drank it with 1 tbsp of butter.
    I also had some cheese and lettuce and drank again almond milk with coconut.
    It really worked well broth and more fat.
    Btw I started a strict diet since nearly 3 weeks. I did it because I had a small breast cancer.

    • Lilja September 11, 2015, 9:28 pm

      Hey Catherine :) I’m so glad it worked! So sorry to hear about the cancer, I hope everything will be ok <3

  • Joss October 13, 2015, 6:28 pm

    I’m only in my third day and I regrettably skipped work today feeling like pooh. After getting some sausage in me and sleeping an extra hour I’m back to mostly normal, with a little bit of ache still in my stomach.

    Anyways, just read your article. Was looking to gain some confidence for tomorrow when I go back to work. I know I have a tendency to sike myself out. So I just wanted to say thanks for the inspiration and information.

  • Anna November 13, 2015, 5:22 pm

    Thank you so much for this article. I knew a lot of it, but the brain fog of atkins flu made it hard to remember! The encouraging tone is slso do helpful!

  • Betsy January 20, 2016, 1:21 am

    I’ve been on ketosis for four months,I didn’t really experienced the ketosis flu when I started but just last weekend I felt all these things. In the four months I was on it I only had 4 beers total,one night I had three and the other one,I also drank Amstel light because it’s carbs were lower them some other beers(4) the past weekend I had 4 in one night and woke up feeling nausea,so I drank some ginger ale(BIG MISTAKE) I felt horrible after that,it felt like the flu and a friend said “yes it’s the ketosis flu”. Is that possible? It really sucked! So if I have a night of carbs I can expect to get the flu?

  • Kim January 25, 2016, 4:52 pm

    I have been on a low-carb diet for 3 weeks now. Yet this flu has been going on for more than 2 weeks now. I’m also a type two diabetic so I don’t know if this is good for me.

  • MARK January 28, 2016, 11:58 am

    Im Dying

  • Tanya January 28, 2016, 10:24 pm

    Hi I’ve been on this low carb diet now for nearly 4 weeks, I lost a stone so far and need to loose 4 stone to go.
    I am now going through what I think is flu but not sure.
    I had a splitting headache for two days. That lead to tunnel vision with rainbow zigzags? Then my whole torso aches I feel like I’ve been attacked and kicked down to a pulp. Especially in my right side under my ribs going up to my shoulder blade. With blocked ears and sneezing. I am never I’ll and feel like am gonna die! Please give me some reassurance x


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