Keto myths & facts

:::begin rant:::

Trigger warning?  Maybe.

Disclaimer: I’m pro-LC (P<0.05), but not anti-LF because LF works better than LC for some people.  And with the exception of things like keto for neurological issues, I think macros take a back seat to many other factors.

Myths: carbs cause insulin resistance (IR), diabetes, and metabolic syndrome.  Carbs are intrinsically pathogenic.  If a healthy person eats carbs, eventually they’ll get sick.

And the only prescription is more keto.




And of course all of this could’ve been prevented if they keto’d from the get-go.

Proponents of these myths are referring to regular food carbs, not limited to things like Oreo Coolattas (which would be more acceptable, imo).  Taubes, Lustig, Attia, and many others have backed away from their anti-carb positions, yet the new brigade proceeds and has even upped the ante to include starvation.  Because “LC = effortless fasting?”

Does this sound sane?

“No carbs ever,
no food often…
otherwise diabetes.”





no one in their right mind would say lentils & beans cause diabetes



“Carbs” is a straw man, because just like how people get angry when “Dietary Patterns” lump animal foods with unhealthy processed foods, they should also get angry when lentils are lumped in with Oreo Coolattas.

Straw man #2: the “well-formulated” diet.  As in, “if keto didn’t work for you, it’s wasn’t a well-formulated ketogenic diet.”  Same is true for carbs.  And every other diet.  Duh.



Fact: nobody really knows what causes metabolic syndrome.

ALL OF THE LONGEST LIVING PEOPLE EAT CARBS.  If carbs were intrinsically harmful, this wouldn’t be true.  Nowhere near it, actually.  The Blue Zones would be the Black Death Zones.  Humans wouldn’t exist.

Non-food contributors to MetS: obesity, sedentary lifestyle, circadian arrhythmia, shift work, crappy sleep, too much artificial light, etc.


Myth: low carb cures IR.

Fact: low carb helps manage blood glucose levels with fewer meds in people with IR.  It’s actually quite good at that.  But the best “cures” are basically weight loss and/or exercise.  “Cure” = can eat a potato w/o hyperglycemia.



“why do low carbers make this insane equivocation ‘carbs = modern junk food that kills you’” -Jane Plain


Part 2. totes ridiculous, anecdotes from the interwebz

Exhibit A.  Dude posts a link which says something to the effect of: “metabolic syndrome is associated with increased joint problems,” then asks: “do high carb athletes have more joint problems [than low carb athletes]?”


This is ridiculous.  It assumes carbs cause metabolic syndrome… in athletes!  1) Carbs don’t cause metabolic syndrome.  2) Athletes are some of the most carb-tolerant people on Earth.  Yes, there are exceptions, but not many.


Exhibit B.  People saying they stopped needing eyeglasses because keto.  I don’t even know what to say to this.





:::end rant:::


For full access to all articles and much more (or if you just like what I do and want to support it), become a Patron! Five bucks a month and there are many other options. It’s ad-free and you can cancel if it sucks 🙂

Also, I’m open to suggestions, so please don’t hesitate to leave a comment or contact me directly at

UPDATED Affiliate links: still looking for a pair of hot blue blockers, Carbonshade  is offering 15% off with the coupon code LAGAKOS and Spectra479 is offering 15% off HERE. If you have no idea what I’m talking about, read this then this.

20% off some delish stocks and broths from Kettle and Fire HERE

If you want the benefits of  ‘shrooms but don’t like eating them, Real Mushrooms makes great extracts. 10% off with coupon code LAGAKOS.

calories proper

Become a Patron!


















Be Sociable, Share!
  • Happy Medium

    are you saying you dont believe the people who claim improved eyesight due to keto?

    • Yaroslav Fedevych

      Maybe they have lost enough fat on their face so it no longer obstructs their field of vision? This is the only plausible thing I can think of 🙂

    • Yossi Mandel

      The only possible case is a diabetic who’s eyesight deteriorated due to hyperglycemia and on keto improved to balanced bg and eyesight returned to previous condition.

      • that’s the theory, but something doesn’t make sense, imo.
        It takes like, ~20 years to develop diabetic retinopathy and eyeglasses don’t help… so the implication is that “balanced bg” rapidly changes the shape of your eyeballs, which is what would actually “fix” vision in this context.

        • Yossi Mandel

          Maybe there’s a point of some returns, then diminishing returns? Maybe eyesight deterioration vs retinopathy? My dr seemed to think it would reverse, is that common thinking?

          • the eyeglass-type of eye problem deteriorates over time… eg, people usually need stronger prescription lenses over time.

            Retinopathy is reversible if caught early, not sure about the early/late ‘cutoff,’ though.

  • rs711

    Someone really said beans/lentils cause diabetes? lol beans/lentils alone don’t cause diabetes.

    The management of BG is not a cure (when considering solely BG). When you say exercise can cure IR…<> do you still consider it cured if the insulin response required to be normoglycemic is still very high? For me cured would required 2 conditions: normoglycemia & a low/normal insulin load to achieve it.

  • Yaroslav Fedevych

    „If keto doesn’t help you, you’re doing it wrong” is much too much like the favorite argument of MLM pyramid proponents, and maybe other shady cult followers. In fact, I just can smell a cult and religious fanaticism whenever I hear this. Whenever someone tells me „X doesn’t help you because you were not doing the REAL X”, I can only respond with a hearty „Go screw yourself with a rusty pipe”.

    (Anyone remember iPhone 4 „you’re holding it wrong” and all hilarity that ensued from the fanbois around the world? This is quite the same.)

    (I know for the fact keto/low carb does help me, because I fit nicely as the typical obese T2DM person. I’m aware someone else’s mileage may vary. But I’m not going to write a book about it, or do a TV/radio show or a podcast, nor am I going to blog about it… and it seems extremely unethical for me to even try to monetize my success story when I get one.)

  • Far- or near-sightedness: the actual physical shape of the eyeball is changed. Treated with eyeglasses. Early age of onset.

    Diabetic retinopathy: 20 years of poorly controlled diabetes? due to cellular damage in the retina, late age of onset, not treated with eyeglasses.

    Theoretically, LC would slow the progression of diabetic retinopathy, but this isn’t the type of eye problem that requires eyeglasses. So someone who claims LC fixed their vision is actually claiming keto rapidly changed the physical shape of their eyeball…


    • Chris

      Good to be skeptical (I am), but can’t dismiss out of hand, since we don’t really know what causes the eye to distort in the first place. Lot of sugar in childhood? IDK Not claiming it’s true, but interested in more study.

      • “Good to be skeptical”

        I agree, but something doesn’t make sense in this example… eyeglasses don’t do much for diabetic retinopathy and keto doesn’t rapidly change the shape of your eyeballs.

        Maybe they didn’t really need eyeglasses to begin with (or something).
        Or maybe I’m wrong.

        • jasmine johend

          I thought it was “floaters” they claimed disappeared or minimized? “The Blue Zones would have become the Black Death Zones” line ever! However what about the internal damage not seen from potatoes/lentils (>insulin to < blood glucose) this is what I get warned of. I'm leaning more towards blue zone these days; just feel better.

          • Yaroslav Fedevych

            No amount of eyeglasses can reduce floaters, or improve vision impaired by excess floaters. If the person was wearing eyeglasses because of the floaters, they were doing it wrong.

            I have 20/20 eyesight and quite a lot of these little buggers in my eyes. No amount of LC has reduced them so far, by the way…

        • Raymund Edwards

          Bill inflammation matters often severe IBS is associated with lots of inflammation that effects the blood vessels esp in the eye

          going keto can resolve this quickly and eyesight does improve where people can do without glasses ( not that shape as changed )

          resolution of oedema

          • “eyesight does improve where people can do without glasses (not that shape as changed)”

            evidence for this?

  • More on what constitutes being “cured”

    Cured of T2DM: normal fasting glucose, normal glucose tolerance

    Cured of IR: normal fasting & postprandial glucose AND insulin

  • Yossi Mandel

    To be fair, Dr. Lustig focused exclusively on table sugar & fructose (a viable hypothesis, and testable). Dr. Attia is all nuance in what he writes, and I doubt we could find a place to quote him blaming carbs that way without ignoring context.

    • Dr. Lustig was low carb & insulin before switching his focus to fructose & refined foods (among others).

      Dr. Attia doesn’t blame carbs, he eats them!

      • Yossi Mandel

        Hadn’t known that about Dr. Lustig, thanks! By the time I started reading and watching him he was on to fructose.

      • Ivan Janssens

        Can you give an example? I have never read something low carb & insulin from Lustig.

        • sure, check out some of his earlier publications on PubMed

      • charles grashow

        Dr Lustig has said one can eat ALL the fruit one wants – with the exception of grapes because fruit has FIBER.
        Q. A lot of the recipes in your book use fruit to add sweet flavors. Was this a way to limit refined sugar?

        A. Exactly. People always say to me, “What about fruit? It has sugar.” But I have nothing against fruit, because it comes with its inherent fiber, and fiber mitigates the negative effects. The way God made it, however much sugar is in a piece of fruit, there’s an equal amount of fiber to offset it.

        There’s only one notable exception: grapes. Grapes are just little bags of sugar. They don’t have enough fiber for the amount of sugar that’s in them. But I have nothing against real food, and that includes real fruit. Eat all the fruit you want. It’s only when you turn it into juice that I have a problem with it, because then it loses its fiber.

  • Abu Sumayah Laughton

    Just because people in the blue-zones lived long lives while consuming a decent amount of carbs, doesn’t mean they wouldn’t have lived longer if they ate less carbs. Furthermore, your comments about eyesight improving on keto come across as super-arrogant. I’ve never heard anyone say this was because of “the eye-shape changing”, do do you not think its possible this may happen via another mechanism?

    • “doesn’t mean they wouldn’t have lived longer if they ate less carbs”

      sure, only meant to say carbs aren’t intrinsically pathogenic.

      “the eye-shape changing”

      how else would eyeglasses become no longer necessary? that’s pretty much exactly what they compensate for

  • Tuck

    Good post. I could quibble with details, but I agree with the thrust.

    Macronutrients just aren’t a good guide. Carbs, fats, or proteins can all be good or bad depending on the details.

    There are lots of confounders, a ridiculous number of confounders. So caution is warranted!

    That said, I think we’re farther along in understanding what causes metabolic syndrome. I’m also pretty darn sure it’s not carbohydrates.

    • agreed!

      But, with which details do you quibble?

      • Tuck

        This: “Non-food contributors to MetS: obesity…”

        I think obesity is a symptom of MetS, not a contributor to it.

        “People saying they stopped needing eyeglasses because keto. I don’t even know what to say to this.”

        LOL. I wish that was true! I did see my vision improve a bit. Your observation about myopia in the comments is correct, but there are other factors in poor vision, and a low-junk diet (which is what keto as practiced by most people today) addresses those factors.

        ” nobody really knows what causes metabolic syndrome.”

        My main quibble is simply that I think we’re a lot farther along in determining what the cause of MetS is. LC as usually practiced also reduces that, so basically we’re looking at a big confounder.

        LC is highly correlated with improving MetS, but we all know that correlation /= causation.

        On the other hand, I do think that a high-carb diet is inferior to an LC one for a number of well-documented reasons. We know exactly what causes tooth decay, for instance, and we have a pretty good idea of what causes malocclusion.

        So yes, over-selling a keto or LC diet is a mistake, but it’s still our best option for an optimal diet.

        • “LC… but it’s still our best option for an optimal diet”


          “why do low carbers make this insane equivocation ‘carbs = modern junk food that kills you’”

          • Tuck

            Not disputing that, Bill. That is part of the reason I agree with you that they’re clearly not the cause of MetS.

            But if my choices are living to 100+ without teeth, or with teeth, I’ll pick the latter, and consider that optimal.

          • …the longest living people have teeth, too 🙂

          • Tuck

            Have you read the book “Two Years Before The Mast”? Interesting, he cures ” weakness of the eyes” by taking a two-year sailing trip. It works, he reports. He also has some interesting discussion about a high-carb vs low-carb (all beef, basically) diet and the effects he notes upon his health. Published in 1840, and available free online

          • doctorsh

            All of the longest living people eat carbs, most likely because their genetics allow them to store and utilize energy they consume from their diet efficiently throughout their bodies.

            I don’t believe IR/MetSyn is just a carb thing. I also believe just as all calories are not equal- I read that somewhere but I can’t seem to remember where ????, not all carbs are equal.

            But if insulins job is to store energy, and we store carbs, protein and fat, and we store these in many different places, —hold on now—, and these places have different limits to how much they can store at one time without putting up any resistance to further storage,— just about there—, then overconsumption of energy can cause IR of different types dependent upon what is eaten.

            A lifelong overconsumption of carbs is likely to cause IR in fat cells. Eating more protein than one needs may cause IR in muscle cells. Same goes for fat in fat cells. This is same concept as how too much fructose causes fatty liver. Each organ or type of cell has a limit and if we go over the limit, IR can occur.

            In diabetics, if they decr fructose as well as other carbs, and the liver and fat cells clear out excess energy storage or fat storage, the IR diminishes.

            Modern junk food being high in processed carbs along with high fake inflammatory fat is a double whammy to good health in people already with IR.

            Some people are blessed with great metabolisms regardless of what they eat. But the majority of people I treat in my practice are not so blessed.

          • +1

            also, I see circadian arrhythmia as upstream (and likely causative) of many of these woes… except maybe “modern junk food high in processed carbs along with high fake inflammatory fat” which are “no bueno” for everyone

          • doctorsh

            Yep. All of these things affect the cells ability to store energy and other items. Our cells live homeostasis and will resist items, energy, etc when it has enough. So circadian rhythms affect cellular resistance. So does inflammation and oxidation. So do many other factors that are mildly causal but not always causal.

  • Daz

    Re the need to wear glasses is due to your eye shape changing…
    C’mon Bill, you can admit it, you have not really delved in to this have you… ?

    • it’s really not that complicated…

      • Daz

        true. not just eye shape tho.

      • Daz

        …another reason for the need for glasses is due to the lens of the eye losing it’s range of focus,
        One reason for this is due to hardening of the lens.
        I say one reason, because perhaps the ciliary muscles play a role here as well.

        This is why someone can end up with plus lens spectacles for close work/reading & minus lens spectacles for distant vision.

  • Chantelle

    Love this … the poor carb has gotten quite a bad rap! And for us people who love our whole food, high quality carbs and still manage to maintain our weight and have excellent insulin sensitivity – it’s music to my ears :-). Rant away!

    • thanks!

    • atomheartsmother

      I am very happy for you that you are able to eat what you want and maintain weight. My wife is also in that happy group. Me…not! If I eat what my wife eats my blood glucose goes off scale. I feel that years of overeating and eating “the wrong stuff” has damaged me, and now the only really effective tool I have is low carb. I do understand that eating only boiled potato for a month would also shift the weight, so it’s not carbs per se. Perhaps it’s down to food combinations. I don’t know, but I still feel that for those of us who have Met S do quite well on LC, compared to other approaches.

      • Chantelle

        For sure those with Met S do well on LC …since their ability to handle carbs has been compromised. So perhaps the focus should be on increasing insulin sensitivity. There are a number of ways to do that through nutrition and exercise and supplements. Met S as well as diabetes are reversible … so I would put the efforts there for a while, then start introducing good carbs very slowly. Good luck!

  • Eve

    But what about the ETC and all the jazz Hyperlipid argues? He seems to offer the most compelling argument for low carb as a means of optimal health, no? Unless you’re one of the few who thrive on a very low fat diet….

    • There are a lot of good arguments for LC…

      but: 1) for some people, LF works better than LC for weight loss

      and 2) the longest living people eat carbs…

      processed junk food gives carbs a bad name

      • NY

        Not sure about the longest living people-argument in favour of carbs. Some longest living people smoked also, does that mean smoking is ok?
        Longest living people didnt grow up drinking fruit juices, coca cola and pepsi so maybe their metabolisms were in much better shape to handle rice and potatoes.

  • Martin

    the new brigade, surely you meant Jimmy Moore but there are others, e.g. Dom D’Agostino also advocates some fasting as an adjunct to a ketogenic diet. Why don’t you invite him for a discussion?

    • Martin

      my point is, macros are not a black and white story. But there are smart people out there who make a very strong argument for a ketogenic diet, that you cannot dismiss with a simple blog post…

      • “is there anything keto *can’t* do?”

        “can someone experience a negative effect from keto?”

        • Martin

          Check out the studies on ketosis that DiAgostino is working on, none of which is dedicated to fat loss.

          There are lots of things that keto apparently can do but if you only judge it from the fat loss perspective you might not be able to see the difference.

    • I’ve been on a few of Jimmy’s podcasts and contributed to his Keto book. And Dom wouldn’t disagree with anything I’ve written here.

  • Guido Vogel

    1) I hardly ever ate junk food, mostly home cooking, 3 meals a day (no packaged foods, no snacks, no McD etc.)
    2) Overweight/chubby since age of 11. I quit eating rice, bread and pasta (and mostly potatoes) at 42 and lost 10 Kg.

    Am I the exception? If not, are rice, bread and pasta (all high carb, around 70%) junk foods? Is it a numbers game (lentils/beans are around 20%).

  • Pingback: Stop Following a Medically Therapeutic Diet "Just ‘Cuz" (a.k.a. The Keto Train to CrazyTown) – Tuit Nutrition()

  • atomheartsmother

    Hi Bill, thanks for the article, which I enjoyed. I am a low carber, not through any religious fanaticism, but because it is a useful tool for me, and a very comfortable way of life. If I feel like an occasional carb binge coming on I go for it, so I don’t feel I’m missing out.
    Personally I am quite fed up of all the flame wars between various dietary choices out there. The truth is that nobody has particularly nailed a ‘one size fits all’ solution. We live in a world where there is far too much food available, by and large, and human beings are not equipped to cope with that particularly well. We should all be given the space to get on with it without being shouted at by others who don’t hold the same ideas (beliefs). It reminds me very much of the shouty flame wars between Apple supporters and MS supporters in the 90s (guys, settle down – it’s just a computer!). Hopefully down the line the anger and frustration between these groups will abate and people will be able to sit down at a table and eat different stuff and focus on our own plate of food, not somebody else’s!