Low-Carb Diets and Increased Mortality

In the longevity community, we often find ourselves deep in discussions about the latest supps purported to extend our lifespan. Yet, an equally crucial is the optimal macronutrient supply. Many members of community support low-carb diets, attracted by various studies that underscore its advantages such as weight loss, enhanced insulin sensitivity, and a reduced risk of certain chronic illnesses.

However, the narrative around carbs and longevity is far from straightforward. For instance, a comprehensive study published in The Lancet Public Health suggests a U-shaped association between carbohydrate intake and mortality, indicating both very high and very low carbohydrate diets could be associated with increased mortality risk, suggesting moderation may be key (https://www.thelancet.com/journals/lanpub/article/PIIS2468-2667(18)30135-X/fulltext).

Furthermore, the European Society of Cardiology has raised concerns about the safety of low-carbohydrate diets, associating them with increased risk of premature death, coronary heart disease, stroke, and cancer (https://www.eurekalert.org/news-releases/599456).

Research published in JAMA Internal Medicine introduces the concept of “healthy” vs. “unhealthy” low-carb and low-fat diets, highlighting the importance of food quality and sources of macronutrients in determining their impact on mortality (Association of Low-Carbohydrate and Low-Fat Diets With Mortality Among US Adults).

Lastly, a study from the Japan Multi-Institutional Collaborative Cohort Study emphasizes cultural dietary differences, showing that low-carbohydrate intake in men and high-carbohydrate intake in women were associated with increased mortality in a Japanese population, pointing to the complex interplay of diet and health outcomes (https://www.sciencedirect.com/science/article/abs/pii/S0022316623721986?via%3Dihub).

This evolving body of evidence invites us to revisit and perhaps recalibrate dietary strategies for longevity. Given these findings, it’s clear the discussion on macronutrients is far from over. What are your thoughts on this ongoing debate?

Have you experienced health benefits or drawbacks from low-carb/keto or high slow carb?

I refuse to believe that a diet which is detrimental to our oral health is actually healthy for the rest of our body. High carb diets are proven harmful, we know pretty well how that works mechanistically too

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When I did keto for 4-5 months, my sensation of hunger vanished. It has remained subdued in the 5 years since I stopped being in ketosis. That has been helpful.


Subjectively, I feel better, sleep better, and have more energy when my diet is more-or-less balanced according to recommendations in the macros.


There may be benefits of the lower-carb/non-ketogenic diet, but there may also be drawbacks. As your third link says,

overall low-carbohydrate and low-fat diets were not associated with total mortality, but a healthy low-carbohydrate diet (lower amounts of low-quality carbohydrates and higher amounts of plant protein and unsaturated fat) and a healthy low-fat diet (lower amounts of saturated fat and higher amounts of high-quality carbohydrates and plant protein) were associated with lower total mortality.

The % of carbs is not listed clearly in these studies or is far above ketogenic levels, as in the first link. And I would have the usual complaint about these not being intervention, but questionnaire-based, trials.

I have experienced great benefits from a keto diet at about 35g carb/day and 70-80g protein/day: stabler blood glucose, lack of hunger, easy to maintain slim weight at 22 BMI, superior and stable energy levels, and a delicious diet. I believe it would work well for many people.


Hey @EnrQay, thanks for sharing your insights! It’s fascinating to hear about the benefits you’ve experienced from transitioning to a keto diet. Your points about the studies not being intervention-based and relying on questionnaires are super valid.

On my end, shifting from a low-carb approach (slow carbs only before aerobic/anaerobic workouts) to including slow carbs in two meals daily has been a game-changer. I’ve seen positive changes in my VO2 max, insulin sensitivity, and the quality of my sleep. Training 3-4 days a week (considering exercise as an important part of my longevity strategy), my muscles (and body) feel better with an appropriate amount of carb-fuel in my diet :slight_smile:

Whether it’s keto, low-carb, or finding a balance with slow carbs, it’s intriguing to see how our bodies react and adapt to these nutritional tweaks. Looking forward to hearing more from the community!


Should not be surprising if you are aware of the top cause of death and aren’t an LDL denier.

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Thanks for the nice response. I’m glad the slow carb approach is working for you. It is interesting how different approaches work for different people and how flexible our metabolism can be sometimes.

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Do anyone actually follow a diet, whether it is mediterranean, low carb or keto? There are a few, sure, but what about most people? I am questioning the adherence levels. If it was so many we wouldn’t have an obesity epidemic everywhere. The best we can do is GLP-1 agonists, adherance to pills is probably much higher.


Since I was a teenager (1980s) I’ve always tried to eat the best diet for health. Going by what I read (government guidelines, studies), usually that meant low-fat and high fiber. I would read any study results or newspaper/magazine article on diet that I came across. Then I read an article about diet that just clicked for me, which challenged my assumptions and made me give low carb a try. Since then I’ve experienced several health benefits from this change. First of all, I lost body fat and kept it off. Then over time I realized that my miserable seasonable allergies went away. Then I realized I wasn’t getting colds–something I was always very susceptible my entire life. Also my craving for sweets went away; I’d always had a huge sweet tooth. Other changes include an elimination of air sickness on flights with turbulence or if the plane had to circle the airport multiple time before landing. Those used to make me miserable. Now I’m fine. I can’t say for sure that me ditching grains and carbs were 100% the cause for my upturn in health, but I’m thinking it most likely was. I’d say the biggest reason it can be difficult to stay on a low carb diet is that we are surrounded by terrible quality, processed high carb food and a culture that keeps it in your face 24/7.


Association doesn’t equal causation. There are several cofounding factors for a keto/carnivore diet such as vaccine hesitancy and low education which may play a role in the higher mortality rate seen in those observational trials.

To your question I think people in far greater numbers are doing low carb keto but we have a nation of sick overweight people. Even millions is a drop in the bucket. The best cure for sweet andccarb craving issues is to follow a keto diet for at least a good while. You will see this comment by numerous people even after reverting to a diet with carbs reintroduced.

I have been following a keto diet for 20+ yrs. I have a starch day about 1x per month. But almost never have any refined sugars. Maybe 4x per year. When I was younger I followed something similar but I added low gi but starchy carbs a hour or so prior to workouts but then was very low carb until the next workout. I was able to develop large awmounts of lean muscle in my 20 and 30s.

Now as I am older, early 50s, I stick almost exclusively keto over 300 days per yr. I feel better, my energy levels stay very consistent along with the typical benefits. Anotherr significant benefit is appetite supression. I have very few days where I feel hunger outside my feeding window. More recently I switch to a shortfeeding window for a single meal of 2-4 hrs. I am now working toward moving my meal earlier in the day from currently 5pm (used to be 7-8pm). Goal is 3pm.

Limiting the number much more than quanitity of protein doses decreases total daily mtorc1 AUC. This was one thing I do not see mentioned but I learned from research and testing many yrs ago. But my target at the time was maximizing muscle hypertrophy not minimizeing mtorc1. Thus was looking for maximizing the number of mtor amino acid feeding curves for the 24hr post wkout.

Amino acid intake stimulated MTORC1 has a limited activity time irregardless of constant or high volume supply of those amino acids. There are numerous studies that even used intravenous suppled leucine, EAA, and BCAA yet the ATK mtor complex S6 etc returned to nominal roughly 3 hours after ingestion or of tge start of constant IV supply. It peaked around the 30-1hr mark There is also a maximial limit to amino initiated mtorc1 activity. 20-30g EAA or 50g complete protein like whey beef egg reaches this threshold at least in fit non-seniors. More aminos will not drive mtor activity higher.

As an example if you had 100gr daily protein intake. A single meal even if stretched out over a few hours will stimulate mtorc1 less TAUC then the same 100gr broken into 2x 50g / 3x 33g / 4x 25g doses separated by at least a few hours. The 4x would actually have the largest TAUC of the combined dosing curves. For EAA I computed this pattern to continue till 10g EAA.

So if you are trying the limit mtorc1 and keep ampk active longer the number of meals matters. Not to mention its effect on insulin. Low carb keto type meals are ideal for this type of TRF as protein needs are rather fixed at least in the short term. Fat makes up the needed energy substrate and has the least stimulation of insulin. Carbs on the otherhand while 2.25x less energy dense stimulate the a large insulin response gram to gram let alone cal to cal.

So for me with the goal of keeping mtorc1 and insulin as the lowest auc as well as frequency of curves a longer 2 hr single meal achieves that while still allowing to a net nitrogen balance that is neutral.

As for any study indicating health issues from a low carb diet. Show my any study where the quality or specific types of food consumed were factored and adjusted for. It does not exsist because low carb does not cause health issues eating low quality processed food does.

Its rather amusing that some of the same people that seem to alway bring up these studies of negatives to low card at the sametime are clamoring to use both acarbose and SLGT2 Inhibitors. So some how the logic is low crabs = unhealthy but consuming carbs then taking a drug to first block their breakdown and absorbtion and another drug to excrete any that does make it to glucose and into circulation. Further it has the added effect of increasing ketones. This diet drug combo though is great and health? So stoping carbs being asborbed…check, have kidneys excrete glucose in circulation…check. It can have the effect of ketone production…check. Or just not consuming these starchy carbs nor any simple carbs achieves the exact these same results without these drugs. Dedcutive reasoning the position is …somehow not taking the drugs to achieve this is unhealthy? The ketogenic diet also supresses SLGT2 as well admittely to a lesser extent that a potent drug.

Keto also achieves very good appetite supression, keeps insulin quiet, tends to cause no effort CR, show to extend lifespan in mice rats.

The research is also starting to show that decease in gut bacteria volume is only transient. Keto diets while severely decrease Bifidobacterium but at the same time significantly increased Akkermansia muciniphila and Parabacteroides spp . Both strongly associated with overall good health.

The hepatic produced ketone B-Hydroxybuyrate makes it into the mucosal lining and has the same positive effects as buyrate. As does the isobutyrate, acetoacetate that are produced in the low carb high protein fat intake keto gut. They are taken up by from the gut lumen by gut epithelial cells These are all used by the epithelial cells for energy same as buyrate but actually more effeicently. It you actually look at the pathway to ATP for buyrate produced by the fiber loving bacteria such as Bifidobacterium. Buyrate is first turned into the intermediates which are Hydroxybuyrate CoA then into Acetoacetate CoA then it enters into the TCA cycle to produce ATP. So the hydroxyburate and acetoacetate in the keto gut are one or two steps, respectivly, closer to ATP and thus more effiecent as fuel then buyrate itself.

You could also very easily incorporate soluble fiber in any low carb diet. Would be interested if anyone knows of any studies at all that look at keto diet induced ketosis with the addition of various fibers know to be strong buyrate producers. What ends up being the microbiome landscape in this situation?

Ketones we seem to know inhibit Bifidobacterium specifically but there are many buyrate producing species and strains. The Hazda hunter gathers have no dectectable Bifidobacterium at all. Yet they have almost no existent metabolic diseases, extremely low cancer rates. Makes me wonder what their life expectancy and general health would be if they had basic sanitation and modern medical care?? So its certainly not a requirement for a healthy gut even in fiber eaters as the Hazda have been forced into out of necessitiy since the end of the 20 and now into the 21st century. They were predominately meat eaters prior to the loss of land.

But mixing keto with heavy fiber supplementation would be interesting to see the gut landscape it produced. Could be a positive, negative, or neutral. Interesting none the less.

Its not as if my keto is consuming pounds of bacon and deep fried hotdogs dipped in a huge jar of mayo. The most processed thing I eat is our homemade sauage and not that often. 80-90% of what I eat we raise and grow ourselves.


Epidemiological studies are pointless. They only serve to conclude a pre-determined bias. There are well controlled studies using a real Ketogenic diet (less than 20g carbs) with outstanding results. After all this is the diet that allowed humans to evolve.


I add about 20g of supplementary fiber (psyllium mostly, but also konjac, inulin, xanthum gum) in order to promote gut health, but I haven’t had my gut biome analyzed. On my keto diet of 35g carbs and 70-80g protein (and a lot of fat), I consume a total of about 40g fiber, and average about 2.5mmol plasma ketones.

I love to see an intervention study of the gut biome of keto vs. keto+fiber.


Myself too. There have been studies that now show the intual decrease in microbial density is transient. Which makes sense. The studies even on mice that have natural high fiber vegiation diets even show healthy gut on ketone no fiber. But what is interesting isif you increaee the carb intake without adding fiber you end up with leaky gut. I think this is clear indications that the ketones are needed to replace the fiber centric SCFA such as buyrate. I also think one of the worst things for a keto diet would be the addition of non fiberous carbs that pull you completely out of ketosis for a significant amount of time. Many people are not careful about using these huge amount of products (highly processed) that are labeled as keto friendly. If there is one thing we know about front labels and regulatory agencies is tgey consider this marketing and having no techincal requirements to accuracy. Much like synthetic motor oil.

People consume these supposed keto breads bars chips etc and very likely its pulling them out of ketosis.

I wish I could handle more MCT oil but more then a couple tb a day and I get stomach upset.

Intoo would very much like to see a hunan fecal bacteria study on health fit subjects that consume a mostly unprocessed keto diet for 12 weeks then add a blended fiber supplement 12 wks Then have the the inverse. Group eating a high fiber diet say 30/30/30 again mostly unprocessed and no-refined sugats. Then switch to keto but with fiber supplement.

We already know the gut adaption going between keto and high fiber.

My concern with my addition of fiber is if it prevents the positive adaption seen such as increased Akkermansia muciniphila and Parabacteroides sp with tge decreased in Bifidobacterium strains. We know that ketones for whateverreason cause a severe decrease in these strains. BI do not think fiber will prevent this if its a direct resultof ketones. If not then fiber would at least prevent some of the decrease. But there are ither buyrate producing species that may not be so effected and should increase with the fiber and decreaee competition of Bifidobacterium. My concern those is Akkermansia muciniphila. It does not do well with high competition of other commensial strains when they have large numbers.

Those are my musing from studying the various data. Ideally I would love fo see both buyrate and isobuyrate strains which I think my be the ideal situation where we tgen have a full complement of SCFA hydroxybuyrate, buyrate, acetoacetate, acetate, propionate and the positive keto effect of increased Akkermansia muciniphila strains.

Currently with my fiber supplement which is all soluble fiber blend I get including tgat from greens 40-60g per day. I xan say this. after intial adaption of about a few days to a week I have no issues with health bowel movements. Obviously on strict keto volume is decreased. Adding the fiber caused a bit of intial gas but quickly disapeared just as the keto adjustment. As expected there is now more volume and moisture. In generalmI amd my entire family have always had health guts with no sensitivities even undercooked meats etc have nevrr been an issue even when others got sick. I attribute this to farm enviornment and all our kids were breast feed. Antibiotic use is near nonexistent. Its heen 20+yrs since last time I was on one, maybe 30yrs.

I am genetically predesposed to being fairly heavy muscled. My daily protein is around 125g 20g nonfiber carbs, the rest fat. When I am after max fat loss I set my fat intake to meet my base caloric needs as completely sedatary and then use the exercise volume to control rate of fat loss. At times I switch from single meal window to allow for a couple small 10-15 g EEA pwo every few hours till my whole food meal. This I found helps preserve muscle when I am at very high cardio volume plus my weight workout. Its still a 14-16 hour fast period. I simply get 2 extra pure EAA of hardly 100kcal each. So very small. But most of the time I keep my standard 2-3hr food window 21-22hr fast. I have been eating this way for a good deal of time and simply am no longer hungry or feel a need to eat more often. Infact I have to ensure I get enough calories in as I move my meal early in the day.


Does psyllium help the gut biome significantly? It is a non-fermentable fibre so shouldn’t feed the bacteria there. It will bulk out stools though.

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I’m currently eating a carnivore diet with the exception of a salad and two glasses of wine on Saturday night, but I can only provide my personal experience with a ketogenic diet.

Six months ago:
Blood pressure 140-160/90
triglycerides were over 200,
A1C was high,
eGFR was 48,
fasting glucose was 120,
LV ejection fraction was also 48!
HDL less than 40
LDL over 200

Six months later:
Blood pressure 115-130/80
triglycerides less than 90
eGFR greater than 60!
Fasting glucose 90
HDL more than 50
LDL 123

I have a steady supply of energy throughout the day with no afternoon nap required, no food cravings at all, psoriasis on elbows has disappeared, mood has dramatically improved!

And the best news of all is that LV ejection fraction is now 63!!

I would be quite surprised if these results led to reduced life expectancy :sweat_smile:.


Congratulations on your remarkable health improvements! It’s inspiring to see such positive changes, especially with your disciplined approach to diet. While your results speak volumes, and it’s clear you’ve found a method that works well for you, it’s always beneficial to consider the broader picture, especially regarding longevity.

Regarding your diet, it’s important to be mindful of the long-term impacts of elevated IGF-1 (Insulin-like Growth Factor 1) and methionine levels, which are often associated with high-protein diets, particularly those rich in animal products. Elevated IGF-1 levels have been linked to an increased risk of certain cancers, and high methionine intake might affect longevity negatively by influencing metabolic processes in ways that could potentially reduce lifespan, according to research published in Cell Metabolism and the American Journal of Clinical Nutrition. These mechanisms are complex and not fully understood, but they underscore the importance of balance and moderation in one’s diet.

I wish you continued success on your journey and hope you find a balanced approach that sustains your health improvements while also supporting a long, vibrant life.

Ketones specifically hydroxybuyrate is known to have a positive effect there.

The one addressable issue with carnivore is the challenge to keep protein intake not excessive to get the total amount of needed calories. You need either extra fat or very fatty cut. I think a healthy protein ratio is 1 g / pound of lean body mass not total pound but certainly 1g/lb BW is more than enough but I do nit see why BF should be included as its the main variable. At my peak I was able to achieve at 5’11" 260lb @ 11% (via hydrodensitometry) which I did with low carb, high fat, so there is no way for the need for some of the extra high protein intakes bodybuilders powerlifters sometimes take 2-4g/lb bodyweight unless they are wanting it treated as a ATP fuel source which is a choice of course but not necessary. Its about proper timing and the amino acids actually needed. The research is all there to support it as are the results.

I am not sure about the negative effects on life span unless those studies looked at humans specifically and in the context of a diet without carbs or ketosis. I personally know of a few Inuit families in AK that have a history of long life (over 100 regularly including the males) They eat very low carb much of the yr. But I attribute much of their health from staying away from the influx of american processedfoids and alcohol/drugs. IIRC one of the elders grandfather’s lived to 120 something. That is of someone born late 1800s with little medical care. The body behaves differently in ketosis. In fact (not keto related) many native american tribes prior to europeans had quite long life spans once they reached adult age from illness or diease. Much better than Europeans of the time.