Effect of long term keto on HA1C

Hi all! I've been low carb for about 4 years now, was metabolically healthy before starting keto (BMI 22, normal cholesterol and blood glucose 90). Since then, my metabollic markers have changed - has anyone else experienced this on a low carb lifestyle? There’s quite a lot of info out there about Lean Mass Hyper Responders and how their LDL can increase dramatically on keto but I haven’t been able to find too much info on the long term effects of keto on fasted blood glucose and H1AC.

I fit into the LMHR category (350 LDL, 78 HDL Trig 53) and found that my fasting glucose and H1AC are now higher than when I started keto (now 94 and 6.0, previously 91 and 5.7) as well as my LDL increasing from 162 pre keto to 350 4 years on. My doctor said I was pre diabetic and high risk for a heart attack and that I should reintroduce carbs to lower my LDL. I paid to test my fasted insulin, as I was shocked by these results and it was 5. So I surely can’t be prediabetic with a fasted insulin of 5 even though by blood sugar and H1aAC is slightly elevated? Interested to know if you have any data on this type of result - ie long term effects of keto on blood sugar/H1Ac on people who were not prediabetic or overweight before starting keto.

Melgar said:

Hi and welcome to the forum @Clairee72 . Your reference to Lean Mass Hyper Responder caught my eye. I thought I was a LMHR, I’m back and forth on it . I’m lean and fit. I was, up until about 10 years ago, a competitive runner. I have a bmi of around 19. I did the very low carb diet for 9 months, but the diet did little to budge my blood sugars. My LDL’s were 4.54 mmol/ls which is only 175.56 mg/dl. Not sure what they were during my very low carb stint. I didn’t have a lipid panel done during that time. I guess they could have been a lot higher, but I went back onto carbs. I’m now on a small dose of statins and they are now at 2.23 mmol/ls. My Triglycerides hover between 0.53 - 0.64 mmol/L or around 20.5 mg/dl. There was a mis-match between my LDLs and my Triglycerides. My HDLs were normal. I know that Triglycerides are low in LMHRs but keto brings LDLs into the very high range. HDL’s are usually normal.

What measurements are you using ” 94 and 6.0, previously 91 and 5.7” - I recognize the HbA1c is a percentage , but what units are you using for the remaining stats ? Are they mIU/L or pmol/L ?

Do you find you lose too much weight on a keto diet? I did. As soon as I drop my carbs the weight just drops off leaving me under weight. In fact I cut back on my carbs just recently, and now my pants / trousers are falling off me. I came off my very low carb diet as I only did it to bring my blood sugars down, which it didn’t, and I lost too much weight, like a lot.

I am not able to answer your question on the effects of keto diets over a long period, and also I was mildly diabetic. There are a number of athletes on keto diets. Not sure how competitive they are when compared with athletes on carb heavy diets.

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Hi, thanks for replying! The measurements were 91 to 94 blood glucose mg/DL pre to post keto, and 5.7 to 6.0 the HA1C % pre to post keto. The lipids are in mg/DL.

I’m active but wouldn’t say I’m an athlete bit much more active than pre-keto. I lost around 3-4 kilos on low carb and feel amazing. Usually train fasted in the mornings. Swim 20 minutes every day in the sea, which probably uses up lots of energy to maintain body temperature. Perhaps the body knows what it needs to do and provides a slightly elevated blood glucose level which remains steady all day rather than dipping and spiking, and there is increased LDL as the liver is busy sending energy around the body? Who knows! But my fasting insulin was low and HomoIR indicated no insulin resistance. I do have some carbs - sweet potatoes- but feel better without carbs such as potatoes, bread etc. I refuse to take a statin as I don’t belive high cholesterol is a bad thing, on the contrary, plus the side effects (muscle pain and impaired mental function/dementia) outweigh any perceived benefit. I think Keto athletes will come to the fore in the next few years, there are certainly a few high performers who have developed pre diabetes or diabetes due to carb loading for so long and have gone keto and found their performance is the same. Look up Professor Tim Noakes (not sure if posting links are allowed?) - fascinating story, and Sean Sako on Instagram. Makes evolutionary sense to train and perform ‘unfuelled’ I guess? Our ancestors wouldn’t have had food before they went out hunting- that’s the wrong way round - the body would have been prepared to hunt optimally when fasted? All very interesting stuff! Anthony Chaffee is very interesting to listen to - he’s 100% carnivore.

MrsA2 said:

I have similar questions. I'm not lean, but not particularly overweight either. Bmi 22 and my lipid breakdowns don't seem to fit any of the current hypotheses I have high ldl and very good hdl, trigs and ratios. My BP is always normal or low.
. I'm going to an event run by heart.uk later this week where apparently I can question experts... I hope they are prepared for me!
I'll report back.

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That’s interesting- are you a type 2 diabetic and are you very active? Have you been able to improve blood sugar by diet? I came across the Lean Mass Hyper Responder when looking at lipid profiles on keto (rather than blood sugar) and the research done has been on measuring lipid profiles rather than blood sugar. I just can’t get my head round the fact that prior to low carb when I was fairly inactive, my numbers for both lipids and blood sugar were ‘better’ than after 4 years of low carb and upping the activity significantly and having lost 4 kilos! Hopefully the experts will be the ones who don’t trot out the ‘saturated fat and cholesterol cause heart disease’ ones, of which there are still many …

HSSS said:

There’s a difference between keto and low carb (which itself is a piece of string). And what that diet consists of, junk processed lazy keto and terrible fats or real natural foods? The proportions of fats, which types, and proteins all make a difference too.

It’s also worth considering that not all LDL is equal. Particle size is rarely tested but makes a huge difference in the potential implications. And what other breakdowns there are of the various other subtypes. Some are beneficial. How are your triglycerides and HDL? Is a CAC scan to actually see how your artery are an option for you (private probably in the UK)?

And honestly the very small differences in your blood glucose and hba1c levels are barely more than tolerance levels, especially if a different machine or lab is used.

And frankly I personally consider your dr a little alarmist based on those glucose results alone. Cause to reconsider and make changes maybe for the ldl, high risk? really? Here in the uk a fasting level of 100 mg is 5.6 mmol, an hba1c of 6% is 42.1mmol and “just” into prediabetic. Insulin results need to be read in conjunction with glucose not alone. Which units and what glucose level at the time?

Has anything else changed? Weight, muscles, health, lifestyle, exercise, medications, stress, hormones?

It’s good to reevaluate our choices given new info and I can see the ldl is a significant change so I’m not dismissing your concerns, just trying to add a little more context.

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Yes that’s what I thought - that he was being alarmist and not looking at the overall picture. I pointed out that my triglycerides were low and the TG to HDL ratio was 0.77, which is great! My numbers have shifted prior to the dietary change and at first glance it does seem like they’ve gone in the opposite (well, opposite of mainstream medical thinking) direction however I’m fitter, leaner and much more active now and my diet is very clean (low carb, animal based - no processed food - mainly eggs, meat, fish and dairy with some veg and sweet potatoes). We did look at hormones so I’m into the final stages of perimenopause so perhaps the bery low estrogen levels have affected the numbers. I could pay for a CAC (I live in Spain) but I’m not worried about by LDL. Was more concerned about the fasted blood glucose and HBA1C being slightly higher than pre - low carb especially as he said I was prediabetic! Need a new doc me thinks!!

ianf0ster said:

I'm slim enough, not active enough and slightly too low on LDL to fit the exact criteria that Dave Feldman et al are using for their LMHR studies.
I have been low carb (20 to 40 gms carbs per day) for nearly 6yrs and in T2D remission for nearly 5yrs, but suffering from a little 'carb creep' before my most recent blood tests.
Following both the LMHR and the C15 stories with interest, especially since I eat what used to seem as a whole lot of saturated fat (often pork belly) and cheese (100gm to 200gms per day).
I found it all seems to be working well for me - so far. Low carb sent my HDL up (nearly doubled, my Trigs low (almost halved) my BG down below uk pre-diabetic levels but my LDL up quite a bit. I had a 3x bypass 15months before my T2D diagnosis, so I'm curious if I'm as healthy as I feel!

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Just reading the Great Cholesterol Con by Dr Malcolm Kendrick - fascinating read.

Clairee72 said:

Yes that’s what I thought - that he was being alarmist and not looking at the overall picture. I pointed out that my triglycerides were low and the TG to HDL ratio was 0.77, which is great! My numbers have shifted prior to the dietary change and at first glance it does seem like they’ve gone in the opposite (well, opposite of mainstream medical thinking) direction however I’m fitter, leaner and much more active now and my diet is very clean (low carb, animal based - no processed food - mainly eggs, meat, fish and dairy with some veg and sweet potatoes). We did look at hormones so I’m into the final stages of perimenopause so perhaps the bery low estrogen levels have affected the numbers. I could pay for a CAC (I live in Spain) but I’m not worried about by LDL. Was more concerned about the fasted blood glucose and HBA1C being slightly higher than pre - low carb especially as he said I was prediabetic! Need a new doc me thinks!!

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Just listened to episode 428 of Dr Rob Cywes podcast on YouTube on LMHR and insulin suppression - very interesting and confirmed my suspicions about blood glucose numbers being slightly elevated in LMHRs so this has allayed my fears about my slightly elevated numbers and also explains why the doc suggested reintroducing a small amount of carbs. He was wrong to suggest I was prediabetic though.

KennyA said:

Hi - I have been on a "keto" diet for over five years since December 2019 - that is, a level of carb intake that ensures I'm in dietary ketosis - and haven't had an "out of normal range" HbA1c since January 2020. I've lost around 40kg/90lbs, unsure thanks to being too heavy for my scales to record weight at the start point., and my waist is now under 32 inches. It's worked, and continues to work, very well.

As far as I'm aware only my BG and weight have altered. Everything else is much the same and in range, although my total cholesterol as calculated is still around 6.9, where it's always been. That is not an issue for me.

BP last week was 125/80. I primarily eat meat with a fair amount of cheese and some veg. I don't eat anything that is "carb-heavy" - bread, potatoes (sweet included), pasta, fruit etc.

I'm increasingly coming to the conclusion that while those of us labelled T2s may all share a problem/symptom (high blood glucose) the cause of that symptom - the actual "disease" - might be quite different. As an analogy, we might all be experiencing lower mileage in our cars but the causes might be different - I have six bags of cement in the boot, you drive everywhere in second gear, he uses cheap and inefficient fuel. Same symptom, totally different causes.

It would follow that what works for you would not necessarily work for me, and that the single approach model beloved of health care systems is not up to the task of dealing with our real problem.

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Yes, although the high blood glucose levels in diagnosed T2 diabetes is always caused by insulin resistance (from what I understand anyway- I have listed to a lot of podcasts by Prof Ben Bikman, which are amazingly informative), which is usually caused by a carb high diet. But my ‘elevated’ (slightly) levels of blood glucose are more to do with just how my metabolic health has regulated itself in a low carb diet, as my insulin levels are low. That’s why doctors should start testing for insulin levels rather than just focusing on blood sugar/glucose levels as too often the blood sugar may still be normal but insulin levels are high (before insulin resistance has fully kicked in), which would mean a much earlier diagnosis. But I do think that going keto/low carb has different effects on people - namely that if you are already very lean/not insulin resistant then you have to be careful not to lose insulin sensitivity, when insulin levels become very low. This can have negative effects on hormones.

AloeSvea said:

I am still in shock as to the thought processes behind a medical professional suggesting someone improves their health with prediabetes by increasing their carb intake! Goodness gracious! These are interesting times we live in re diet, for sure,

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Although he misinterpreted the results by thinking I am prediabetic without knowing my fasted insulin (which was 5 when I tested), the suggestion to add a small amount of carb back into my diet would improve insulin sensitivity, which can become a problem of insulin levels drop to 2-3. I’ve come to understand that it’s normal on very low carb or carnivore to have a slightly raised blood glucose just due to how the metabolism has adjusted- it may be slightly higher to compensate for lack of carbs but there are no sudden spikes.

Melgar said:

That’s interesting @Clairee72 . I’m not on a low carb , high fat diet, but I do take PPI’s for peptic ulcer disease. These PPI’s are known to cause intestinal overgrowth of the gut causing further issues such as SIBO and C. Difficile. So, this led me to look at diet and the gut. Whilst looking at these potential problems on being on long term PPIs I came across an article in the SciTechDaily. This new study looks at the effects of meat based, high fat diets on the microbiota of the gut. The article suggests that diets such as low carb diet, high fat diets, which are low in fibre, may promote colorectal cancer by altering gut microbiota and increasing the production of metabolites which are apparently linked to cancer development over the long term.
Reading into the research this possible cancer risk can be alleviated by increasing fibre in the diet.

Here is the link if you wish to read the article in its entirety.

https://scitechdaily.com/low-carb-diets-may-fuel-colorectal-cancer-concerning-new-study-reveals/

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Thanks. There’s a lot of discussion about low fibre around carnivore diet, and gut microbiome and health. Very interesting!

Clairee72 said:

Thanks. There’s a lot of discussion about low fibre around carnivore diet, and gut microbiome and health. Very interesting!

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That also reminded me that I haven’t made sauerkraut for a while - great for the fibre and the healthy gut bacteria.