How a Doctor from Germany Treated Keto Rash While Staying In Ketosis By Slightly Increasing Carbs

Earlier this year I received an e-mail from Rainer Haarfeldt MD, a physician in Germany.  He described how he managed to treat keto rash while staying in ketosis simply by increasing his carbohydrate intake by 10 – 20 gm per day.

While this wasn’t possible with me, the fact that it was effective with Dr. Haarfeldt definitely makes this a method worth considering.

Hey Philip,

My name is Rainer, I´m from Germany and I´m a medical doctor for internal medicine.

I´m engaged in endurance sports (mountain running, biking, cross-country-skiing)f or 35 years and work with many athletes (endurance sport).

I tried the ketogenic diet first in 2013 and suffered the keto rash after one week in ketosis till I stopped the diet (two months).  I did it again in 2014 (March and April) and October and everytime the keto rash came after one week in ketosis. I couldn´t do anything against it.

First I want to thank you for the great job of making the homepage about the keto rash – it was a relief for me to see, that I was not alone with this problem.

I read about adding some carbs to avoid the rash and tried it this year. I started the ketogenic diet on February 1.  After one week really low carb (about 20 g/d) the rash was there and then I started to add 250 ml vegetable juice (3.5 g carbs /100ml) – makes about 8g carbs per serving – in the morning and for dinner and the rash disappeared almost completely.

Then I went down on once a day and the rash came back.

Again twice a day – the rash disappeared. I check the ketosis with blood ketones and the ketonix sport and I was always! (two month) in ketosis – the ketone levels between 0.5 and 3.5 mmol/l.

When I was on a trip in the mountains,Ii used a bar with almonds and honey (about 10 g carbs) and it worked the same way. So, for me it was possible to stay in ketosis and avoid the keto rash with only slight changes.

Only wanted do let you know about it – may be, it can help other people to!

I asked a little more about his regimen to clarify things and this is how he responded:

Hey Philip,

You are completely correct! I normally eat really low carb during ketosis, because I hate to count and weigh my food. So mostly fat, moderate protein, nuts and so on. Salad and vegetables, I don´t like during ketosis, so I mostly avoid them.  Fruits I don´t eat at all.

My fiber I get from inulin and self fermented sauerkraut. I guess, I eat not more than 20 to 30 g of digestible carbs a day.

The additional 10 to 15 g a day carbs from easily to digest sources stop the keto rash completely and I´m far away from falling out of ketosis.

For me there seems to be no connection between the ketone body – levels and the keto rash… I would rather suggest a connection to the gluconeogenesis occurring after sport sessions. The additional carbs seem to stop or slow down the gluconeogenesis somehow… (I also checked the blood glucose and the readings were much more stable and lower with the additional carbs).

Most recently he just sent me this update:

Hi Philip,

Thank you for your response. For me it´s no problem, if you mention my full name together with “MD”. If someone wants to contact me for further information or questions – no problem.

I have some more information for you. In July I competed in a 4-stage long-distance trail-running race (4-Trails) here in Germany/Austria. I wanted to test, if the ketosis is usefull for these long distance competitions.

I entered ketosis 7 weeks before the race, after one week the usual keto rash, which disappeared with the addition of about 10 to 20 g carbs (vegetable juice).

The training for the race was perfect, also more than 20 hours of training in week 4 before the race made no problems and I felt perfect and in very good shape and the keto-rash did not come back.

During the race the situation changed from the first day on. After the first stage the rash was back as strong as never before and during the next days my fitness decreased in an for me unusual way. The most important thing was, that my muscles did not properly recover after the stages and the keto rash became worse every day.

After the 3 stage I stopped the “experiment” and went out of ketosis. I could finish the race, but the result was not as good as expected.

After one day of normal nutrition (still paleo, but not ketogenic) – the rash started to disappear.

For me, this was a strong hint, that my assumption, that the keto rash is connected with gluconeogenesis, is true. Under normal circumstances (little bit more carbs, normal training) it was possible to avoid a higher rate of glucogenesis and thereby the ketorash.

During competition I slightly went over the intensity level, where my body is using only fat as fuel and I had to produce the needed carbs through gluconeogenesis. The needed protein my body took from my muscles (bad muscular recovery) and the higher rate of glucogenesis made the keto rash “explode”.

For the future I will use the ketogenic nutrition in times of basic endurance, high volume training, because its a perfect tool, to improve the fat burning efficiency of the human body. For competitions I will use the paleo carb backloading protocols (Cordain).


If you’d like to contact him directly he kindly provided his e-mail:

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  1. Victor

    First of all… I’m really thankful for your site. I stumbled onto it a couple days ago and has just been reading and digesting as much info as I can. I got the rash last week, which was about 4 weeks into ketogenic diet. This is the first time I’m doing this, so I may not have been in ketosis from the start.
    Anyway, I started at 192lbs and about 20% BF, and lost about 10lbs in that 4 weeks. It is now the fifth week, and it’s weird that the weight loss has almost completely halted. I understand that rapid weight loss in the beginning is normal, due to the water being removed, but it’s just odd that I’ve lost less than 1lb in a week. I think some of your readers also reported similar observation.

    My blood ketones was 5.0 when I felt like the itch was getting a bit unbearable, which was 2 days ago. Since then, I’ve tried applying tea tree oil. Yesterday, I must have consumed enough carb that when I measured, my BK was 0.3, which means I’m out of ketosis. A weird thing that I noticed was that I felt kind of fatigue, and when I exercised, I felt low in energy.

    The stagnation of weight loss and the low energy makes me think that Dr Haarfeldt may be onto something with the gluconeogenesis thing. Although, I think it’s just part of a piece of a puzzle as it wouldn’t explain why the antibiotics would work and not come back even if someone continue to stay in ketosis…

    When I woke up this morning, I felt the itch was less, and the rash has subsided a little. I decided to go keto again and just have eggs, coconut oil and butter for breakfast, green beans, cheese, chicken and beef for lunch… I measured my BK after lunch and it was 1.9. I continue to apply tea tree oil, al though I’m not sure if it helps or more of a placebo effect. But the rash did get a little itchier towards the evening.
    I worked out in the evening, but did not feel the same low energy I did yesterday. Afterwards, I took a protein shake, had dinner which may have had a bit of sugar in it… after which I measured, and my BK is 0.5. Right now, it’s almost 10pm, and I feel like there’s not much itch in the rash anymore.

    I intend to stick with the very low carb especially during the day, and maybe relax a bit for dinner. So, I’ll report back on my progress. Might try to do this n=1 experiment as long as I can bear before I give up and go down the antibiotics route.
    Meanwhile, what are your thoughts on the gluconeogenesis theory?

    1. (Post author)

      Keep us posted as to how your n=1 works!

      One thing you can explore is a cyclic keto diet. Stay hardcore keto during the week, then eat carbs during the weekend. You may be able to find a balance between staying in ketosis the majority of the time while keeping your rash at bay.

      I’m not sure about the gluconeogenesis theory. I’ve been trying to look into it more.

      There’s a tumor out there called a glucagonoma that secretes a lot of the hormone glucagon, which stimulates lipolysis AND gluconeogenesis… and guess what? It causes a rash!

      I thought it was onto something, but the rash is completely different and in a different distribution. So… who knows.. there may or may not be a relationship, but none that I’ve managed to detect.

  2. Victor

    Interesting info about glucagonoma… I agree the rash definitely looked different. Anyway, I think i screwed up my lunch & dinner, tonight i measured my BK at only 0.2. But, as expected the rash seems to be going away. I’m actually pretty amazed how quickly the rash subsides due to a lower BK.

    Not sure if it’s related or not, but I’ve had a mild flu-like symptoms, ie. runny nose, sore throat about the same time the rash started appearing… wondering if the rash is due to a compromised immune system… or maybe just a red herring. I’m still coughing a little at this time.

    I’m probably gonna just use this place as a journal for my progress. I’ll try to get back into ketosis tomorrow… I guess I should tell the mrs. to cook my food separately to avoid contamination from the carbs.

    1. (Post author)

      Please come back with updates, as I’d love to know your progress.

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