Carbohydrates: Let’s All Take a Breath

Guest post written by: Amy Berger


Dr. David Perlmutter’s appearance on episode 200 of the Paleo Solution podcast stirred up a bit of controversy. It was disconcerting to hear one of the premier clinicians in the field of neurology present a hardline stance concerning carbohydrate consumption. With many of us consuming higher amounts of carbohydrates to fuel athletic performance, lighten the food budget, or simply enjoy a little more variety in our diets, hearing a medical expert draw a line in the sand against seemingly all carbohydrates left a few of us anxious, worried, and starting to question what we’re feeding ourselves and our children.

In light of that, I think it would be useful to present some thoughts about all this. It’ll be a pretty high-level view of things, or, as Robb might put it, “the 30,000 foot view”. On the way up from the ground, we’ll get to see lots of pretty, individual trees, but once we reach cruising altitude, there’s a heck of a beautiful forest to take in, too.

The Big Question

What will prevent mental and physical degeneration? What are the exact actions we could take that will have each and every one of us winning 100-yard dashes and chess tournaments well into our nineties? In case you’re pressed for time, let me spoil the ending for you right here and now: we don’t know. We can’t say with absolute certainty precisely what types and amounts of physical activity will keep us agile and strong. We can’t say exactly how many grams of fat, protein, and carbohydrates will keep every single one of us healthy, pain-free, and firing on all cognitive cylinders for the rest of our lives. Sorry kids, but that’s the truth. For all the studies that have been done, all the programs and protocols that exist, and all the logical sounding theories, the scary fact is: We. Don’t. Know.

If you think this lack of definitive answers gives you free rein to toss back as many boxes of donuts and barrels of soda as you want, from the comfort of your horizontal perch on the couch where you spend ten hours a day, guess what? You already had that. You’ve had it all along. Because diet and lifestyle recommendations—whether they come from the Paleo side of things or somewhere else—are not laws. They’re not commandments. They’re simply information, for you to apply to your own life as you see fit.


Just because we aren’t absolutely sure of everything doesn’t mean we don’t have some pretty good working assumptions. So yes, the bad news is, we don’t have all the answers. And even when we think we have some answers, we often have to go back and revise them in light of new data. But the good news is, even though we don’t know—and really, can’t know—everything, we’ve developed a darn strong framework to help us make informed choices about what we eat and how we live. It’s called ancestral health. (Maybe you’ve heard of it…) We don’t have an iron-clad, step-by-step procedure for guaranteeing we’ll all be intellectual and physical ninjas until we drop dead from happiness as we reach the top of Mt. Kilimanjaro at age 112. But what we do have is the most sensible and most comprehensive approach to all this that we’re currently aware of, based on research that has been done and is still being done by some very brilliant people across a wide variety of disciplines.

So we have an ancestral framework, not a historical reenactment, right? That’s why some of us go running barefoot, but still sleep in a bed. Or why we eat bone marrow but also have Facebook accounts. These things aren’t mutually exclusive. In keeping with this 30,000-foot view, we could ask ourselves what the environmental and dietary inputs are that we’ve evolved to expect, and what are the likely consequences when we spend most of our lives without these inputs?

Again, we can’t know these answers with absolute certainty. But we have some fairly educated speculation that we can use to take action and hedge our bets, rather than throwing our hands up and doing nothing because of “paralysis by analysis.” And the framework we have can offer some insights that might help us make sense of Dr. Perlmutter’s stance on carbs, and decide how we want to proceed in our own lives.

…And the Possible Answers

As we get into this, let’s remember the patients Dr. Perlmutter likely deals with: they are demented, inflamed, in chronic pain, and otherwise suffering the effects—or so we presume—of diets & lifestyles out of sync with what evolution has conditioned our bodies and brains to expect. To put it bluntly, these people are broken. So while it’s important to know how to “fix” these people, perhaps even more important is to figure out how to not break in the first place. And we think the ancestral health approach offers some pretty great guidelines for this—probably better than anything else currently on offer. Will we be proven wrong? Only time will tell. Time, and a seriously huge prospective study that will likely never be done. (Anyone got an extra couple hundred million dollars lying around?)

But just because we can’t know everything for sure doesn’t mean we don’t have some suspicious looking smoking guns. For the purpose of not “breaking” in more ways than there’s room to mention here, one of the most powerful things we can do for our health—or so we currently believe, based on an exponentially expanding body of research—is maintain insulin sensitivity and keep blood glucose levels in check. One effective way to do this is to keep our carbohydrate intake at levels suitable to our individual physiology. This is where things get gnarly. (Or, as Robb might say, where people’s panties start bunching.) People get very anxious when this topic comes up, and for good reason. Some people are perfectly content to eat less than 30g of carbs a day for the rest of their lives, but others prefer some sweet potato hash now and then, a handful of berries, some butternut squash, and maybe even some grain-free dessert splurges made with maple syrup and dried fruit. But one thing we probably all agree on is that none of us wants to end up a financial and emotional burden on our loved ones. If poor health is scary, poor neurological health is downright terrifying. And it seems like this is where most of the trepidation regarding carbohydrate consumption comes from. Are we doing ourselves and our children a disservice by consuming vegetables and fruits that have been part of the human diet for millennia?

What is the exact amount of carbohydrate that, when consumed over a day, a week, a year, or a lifetime, could potentially bring about diabetes or Alzheimer’s? Would that amount be different for a librarian and an NHL player? How about a 5’2” Korean woman and a 6’4” pureblooded Cherokee man? The mere nature of those questions should show us how difficult it is to posit answers. Is a once-a-month ice cream bender in an otherwise lower-carb diet going to cause us to become insulin resistant? How about a post-workout whey protein & banana smoothie? Will a ketogenic diet prevent all illnesses related to blood glucose dysregulation? If so, is that true for every single human being? And if that’s so, would the ketogenic diet need to be followed for an entire lifetime? We just don’t know. No one can tell any of us the exact number of carbohydrate grams that each of us, as individuals, can consume with no adverse effects on long-term health.

But looking at this through the evolutionary lens and combining that with what we know about physiology and biochemistry can give us a good sense of how to feed and water ourselves. Good enough to prevent every single illness, wrinkle, and moment of forgetfulness we would otherwise encounter sixty years from now? We can’t say. And if you’re looking for someone who can tell you that their approach is THE way, the best way, and the only way, for every human being on the planet, I encourage you to make sure your BS meter is expertly calibrated and fully charged.

Informed by Evolution & Anthropology

Most of the conditions Dr. Perlmutter regularly treats are the results (or so we currently believe) of insulin dysregulation, mitochondrial dysfunction, gluten intolerance, and autoimmunity. So in order to “not get broken,” we would want to avoid foods and activities that could potentiate these things, and include things that are supportive of health at the macro and micro levels. This matches up with the Paleo template of eating real, whole foods, restoring and maintaining lifelong insulin sensitivity, and preventing or reversing leaky-gut induced conditions by avoiding foods that are problematic for us almost as nicely as Africa and South America fit together according to the theory of continental drift. Based on our evolutionary framework, as general guidelines for keeping ourselves in good working order for as long as possible, we can list sleeping when it’s dark out, getting physical movement the way Mark Sisson describes it (lots of low-level activity like walking; lifting heavy things a couple times a week; and going all-out on speed & effort once in a while), getting some sunlight on our bare skin, not sterilizing and irradiating every molecule we come in contact with, and managing stress levels (feelin’ groovy as much and as often as possible, but with occasional periods of pants-wetting fear, limb-tearing anger, and/or stomach-churning anxiety).

And then, of course, there’s diet. Like I said in my comment on the podcast post, “just because ketogenic/VLC diets seem to do a stunningly fantastic job of healing in some conditions for which conventional pharmaceuticals have largely failed or even made things worse, doesn’t mean every single one of us needs to be on a ketogenic diet our entire lives to prevent these conditions.” I used the metaphor of an insect infestation: That “calling an exterminator and having him fumigate your house kills your ant infestation doesn’t mean setting off bug bombs in your house is required to prevent the infestation in the first place. You can use other, less drastic measures to ensure you don’t need the more extreme solution later on. (Better insulation on doors & windows, not leaving food out, etc.)”

So what are the less drastic measures we can implement when it comes to diet? Since poor glucoregulation seems to be one of the larger issues (if not the largest) behind several metabolic and degenerative conditions, the carbohydrate question is especially important—and particularly vexing. In light of us not being able to say much of anything with 100% certainty, it’s impossible to define the amount of carbohydrate that will and will not lead to insulin resistance and related health complications. There are just too many factors at work to be able to make blanket statements that apply to the ethnically, geographically, and physiologically diverse species that is Homo sapiens. In the oft-cited Kitavans and Inuit, we have two populations that remained robust and healthy on radically different diets. Does this mean a Kitavan would thrive on whale blubber and an Arctic dweller would remain her strong, healthy self on starchy tubers and fruit? From lactase gene persistence to skin pigmentation, we assume certain physiological adaptations have occurred through the millennia. Why should carbohydrate tolerance be any different? We shouldn’t dismiss the possibility that groups of people with certain ethnic and geographic origins can consume more carbohydrates than others long term without ill effect. And based on studies of traditional populations (by Drs. Price, Lindeberg, Eaton, etc.), it’s safe to say that consuming carbohydrates, per se, does not cause the myriad health problems we see today. Context matters. Can I say that again? Context matters. (Or so I think. In the proud tradition of responsible scholars, I reserve the right to revise my position if necessary.)

But let’s stick with our big picture focus: if we try to stay guided by combining common sense with our evolutionary lens, it’s possible that 200 grams of carbohydrate from potatoes, parsnips, yams, and beets have a different metabolic effect than 200 grams from Mountain Dew and Oreos. It’s also possible that those 200 grams—regardless of where they come from—have a different effect in someone who was born with compromised insulin sensitivity and digestive function, and someone who, for reasons of sunlight exposure, sufficient sleep, good stress management, reasonable levels of physical activity, previous generations’ nutrition, and, for all we know, Venus rising in Aquarius the day they were born, are able to process much more carbohydrate than their next-door neighbor.

Is there a difference between eating some honeydew or a sweet potato now and then, versus fruit cocktail canned in heavy syrup eaten for breakfast every morning along with whole wheat toast and a 20oz glass of orange juice? Nutritionally speaking, yes, of course there’s a difference. Biochemically, in the non-metabolically broken, there also seems to be a difference. But the broken people—the ones who fail to process most carbohydrate properly—would likely do well to avoid both options, at least while they’re still in the process of repairing themselves. Some people will be able to repair themselves to the point where they can increase the amount of carbohydrate they eat. Some won’t. Some might have done so much damage for so long that they’ve backed themselves into a metabolic corner and the only way to keep it from getting worse is through medication and/or a drastic diet.

Would Dr. Perlmutter’s recommendations for everyone, across the board, to follow a lifelong low-carb diet largely prevent “the diseases of civilization”? Probably not all of them, but it would likely go a long way in the right direction. Does that mean a low-carb diet is required to prevent them? Maybe not, but what is probably required is lifelong good glucoregulation—whatever that means for YOU. Maybe it means under 50g of carbs a day, maybe it means under 150. Maybe it means 200 on the days you have a tough workout, but 40 when you go a couple days being sedentary. You can’t know unless you pay attention to your own body. (For anyone who thinks the original Atkins diet was nothing but bunless double bacon cheeseburgers, I encourage you to read his earlier books, because the much-maligned Dr. A was a strong proponent of finding your own individual level of carbohydrate tolerance. For some people, that might be 200g and leaves room for rice and fruit. For others, it might be 50g, in which case they’re better off sticking with broccoli and eggplant.)

Let’s bring this back to what we’re all after here:  not getting broken.

In my original comment, I said that if we smell the smoke long before the fire gets out of control, we can spare the house from burning down. Our bodies are only too happy to give us smoke signals all the time. Do we get irritable if meals are skipped or delayed? Do we want to maim, torture, or kill everyone in sight until we get fed if it’s been a few hours since our last meal? (Kudos to whoever came up with the word “hangry.” It’s golden.) Do we have times throughout the day when we feel fuzzy-headed or forgetful? These can be indicators of blood glucose gone awry. And you don’t need a fancy test or even a doctor’s appointment to interpret these smoke signals and find out what’s going on. How about a $20 meter from the corner drugstore? We wouldn’t go on a cross-country drive without occasionally glancing down at the gas and oil gauges. Why should we drive through our lives without checking the numbers once in a while? When we see fasting blood glucose, A1C, and triglycerides inching upward over the years, that could be a sign we’re eating more carbohydrates than our body can handle appropriately. (With the understanding that A1C might not be an ideal marker for healthy people already following Paleo or low-carb diets.) We don’t have to wait for full-blown diabetes to come knocking on the door and we’re all but forced into cutting carbohydrates (or dosing up the insulin, along with all the great things that can lead to). We can self-check now and then to see where we are and do modest repairs before the wheels completely fall off the wagon.

That’s the good thing about these numbers. Unlike a smoke detector that only goes off when there’s already smoke—and possibly a fire—in the house, some of the biomarkers we believe offer clues about our health start moving unfavorably long before we’re diagnosed with anything. Overt symptoms sometimes take years to manifest, and they only show themselves when the problem has existed unchecked for so long and has become severe and/or widespread enough that the body can no longer compensate for or hide it. So keeping an eye on some of these markers over time can be a kind of metabolic GPS, telling us when we need a course correction.

But let’s remember that even these numbers are imperfect guides. If fasting blood glucose at 100 mg/dL makes someone “pre-diabetic,” how different is that from someone at 99? Or what about cholesterol? If a doctor pushes statins on someone with total cholesterol of 200mg/dL, does that mean the person at 199 is totally in the clear? (Just an example. I’m fully aware that 200 is not high and the way the “treatment” of cholesterol has been medicalized is beyond ridiculous.)

Okay, that’s all well and good, but WHAT ABOUT CAAARBZZZ???

Let’s remember that humans are nothing if not opportunistic omnivores. We eat what we can, when we can. If we think about this from our ancestral/evolutionary viewpoint, it makes sense that we would have made use of the flexibility to be sugar burners or fat burners seasonally. That is, consuming fruit and sweeter vegetables in summer to “fatten up” for the relatively leaner period of winter, when we would have been closer to a ketogenic diet, accompanied by less physical activity and more rest. Almost like a human hibernation period. But there are other factors at play besides our carbohydrate consumption: considering the amount of darkness during winter away from the equator, we likely would have gotten a lot more sleep. Our ancestors weren’t waking up at 4:30 or 5:00 in the morning every day, all year long, to go to work or hit the gym, whether it was light or dark out, hot or freezing cold. Our modern diets & lifestyles have made it so neither the famine nor the darkness ever comes. These environmental inputs we’ve presumably evolved to expect are absent from our 21st Century lives. We have to intentionally impose these conditions upon ourselves because they no longer occur naturally for us. But it’s not difficult to do. It’s as simple as implementing periods of ketosis, fasting, or low-carb once in a while (if you don’t do it as your baseline anyway), and sleeping in the dark. (It also couldn’t hurt to get outside in the fresh air now and then, preferably in a green, woodsy area, but that is a whole separate topic.)

So back to carbs. Dr. Perlmutter likely deals with younger people who’ve been eating the SAD all their lives, or, in the case of baby boomers, for enough years that their health is completely, totally compromised. It makes sense that people who are quite far gone would need a strict, no-nonsense dietary intervention as a therapy. They don’t have the luxury to play around with dipping their toes in the water to test things out. They need to do a cannonball into the deep end. But this is what makes the most sense after the damage is already done and we’re trying to reverse it, stop it, or at least slow it down a little. This does not automatically translate to this same dramatic protocol being required to prevent the damage from occurring in the first place.

If you stumbled upon Paleo-style eating early enough in your life (or your children’s lives) to understand the basic approach of keeping omega-6 consumption low, staying away from gluten, eating the best quality meat & produce you can afford, and eating real, whole food carbohydrates to match your individual metabolic sensitivity to them or to satisfy your physical performance goals, then there’s a good chance you’re not going to accumulate this lifetime of extreme damage. You will accumulate some damage, though, make no mistake about that. The glycated proteins and advanced glycosylation end products (AGEs) Dr. Perlmutter mentioned are normal, natural parts of aging. But they’re supposed to happen slowly, over a very long period of time. We’re all going to get old and die. We can’t change that. But what we can change are obese first-graders, 35-year-olds sidelined by rheumatoid arthritis, and 65-year-olds (still young!) with dementia so severe they require live-in care.

After Dr. Perlmutter’s interview aired, people started questioning their carbohydrate intake, and some wondered whether it was safe to feed their children fruit. If you’re feeding your children a Paleo diet most of the time, they get outside and run around regularly, and you aren’t hosing them down with antibacterial gel every time they come and go from the house, they are likely WAY ahead of the curve and it’s hard to imagine that a bit of fruit or starch here and there would derail their long-term health. We might never know exactly what prehistoric man ate, but we have a pretty good idea of what he didn’t eat. (Pop-Tarts and gas station cappuccinos come to mind.) The basic ancestral dietary framework—including carbohydrates—will get us, say, 85% of the way there. The extras—better sleep, intelligent exercise, lower stress, some sunlight and fresh air—will maybe get us to 96%. As for the last 4%, it should be weighed against our quality of life—against the simple pleasures of dining out with friends, going apple picking in October and eating some of the apples, or sleeping in on a Saturday morning during a blizzard instead of scraping ice off your windshield in the dark so you can make your 6am workout.

You are the one walking around in your own body and in your own life. Everything has a cost/benefit associated with it, from the volume and frequency of the exercise we do, to the amount of omega-6 in the nuts & seeds we eat, to the amount of fruit we consume. We have to make these choices and tradeoffs for ourselves. We can live to be 114, but how much will we enjoy those years if we spend the last 75 of them never, ever dining out with friends because …*gasp*… something might have been cooked in canola oil? Or we become so afraid of fructose that every summer for the rest of our extra-long, long lives passes without the juice of a ripe peach running down our chin?

The good news!

This post started off with the bad news—that we don’t have all the answers. So let’s end it on a better note. One thing we do know is that the human body is remarkably, stunningly resilient. Given proper care and feeding—and thanks to the glorious process of cellular turnover—our bodies are capable of staggering acts of healing and regeneration. The testimonial section of this and other Paleo sites are repositories of personal accounts detailing seemingly miraculous turnarounds of arthritis, diabetes, heart disease, obesity, lupus, MS, digestive disorders, infertility, anxiety, acne, depression, and more. So while we can’t say with certainty exactly how many grams of carbohydrates each of us should be eating to cruise into old age happily and healthfully, I’d say we just might be on to something here.



Amy Berger, M.S., is owner of Tuit Nutrition. A proud U.S. Air Force veteran, Amy spent years doing “all the right things,” but failed to see the expected improvements in her health and fitness. By shifting to nutrient-dense, unprocessed foods (especially some of the things we’ve been told not to eat!), she transformed her health and physique, and now shares the lessons learned with those still struggling. She is especially passionate about showing people that losing weight and achieving vibrant health do not require starvation, deprivation, or living at the gym— and that real men and women need REAL FOOD, not lettuce! 




Categories: Anti inflammatory diet, Athletic Performance, General, Paleo/Low Carb


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  1. says

    I love the debate this has stirred up.

    What I don’t like is that many people approach this subject from the point of view that significant level or carbs is the norm and that a high fat/ extremely low-carb diet is a deviation. It really should be the other way around.

    It’s not “prove to me that low carb is good” but rather “prove to me that moderate levels of carbs are good.”

    Excellent article!

  2. says

    The burden of proof lies in the person making the claim. If David Perlmutter, or anyone else, is claiming carbohydrates cause degenerative diseases then it is up to him to provide evidence for that claim. Just because ketogenic diets are therapeutic for neurodegenerative diseases doesn’t mean carbohydrates cause them.

  3. Martin says

    Why worry? If you do what you do, and feel great and have no second thoughts, why be concerned? I eat very low-carb and find the idea of safe starches interesting but useless in my particular case and so not worrying at all.

    If dr Perlmutter makes you worried than maybe, just maybe, you feel that not everything is OK.


    >> It was disconcerting to hear one of the premier clinicians in the field of neurology present a hardline stance concerning carbohydrate consumption.

    Not at all :-)

    >> With many of us consuming higher amounts of carbohydrates to fuel athletic performance, lighten the food budget, or simply enjoy a little more variety in our diets, hearing a medical expert draw a line in the sand against seemingly all carbohydrates left a few of us anxious, worried, and starting to question what we’re feeding ourselves and our children.

    Many of us consume very low amounts of carbohydrates and lots of good fats that allow us to fuel athletic performance across the wide spectrum of physical actiivities (from sprints to ultramarathons and from high intensity bouldering to all day alpine climbing).

      • Mike says

        Indeed, might work for some and for a while. But not for long. I have
        read Jeff Volek and Stephen Phinney books and some other their published
        studies. I followed a VLC/keto diet for about 8 months. Also started
        doing HIT strength training, like Doug McGuff and Fred Hahn have written
        about. And a lot of walking, about 5 miles a day.

        During the first few months I felt great, lost some weight and
        performance was fine. As I got fitter[4 to 5 months], felt it was time
        for more volume of exercise. So added two sprint days to the above.

        At about the sixth month I started to feel lethargic, less motivated to
        do the HIT and sprints; less energetic and sleep started to suffer. I
        took this as a sign that I was not eating enough. So ate more and that
        help a bit at first.

        Things got worse at the 7 to 8 month mark. The symptoms above got worse
        and started to gain weight. That is when read more from Robb, Jaminet’s
        and others, on carbohydrates[CHO]. Added some CHOs back about 50g to
        100g on non workout days and a little more[about 100g to 150g] on
        workout days; from safe starches, eaten at night. My sleep improved
        right away, energy came back and to my surprise, this did not affect
        doing intermittent fasting[IF]. It actually made IF easier.

        Blanket statements that all CHO are bad, for everyone all the time does
        not make sense to me anymore. I did not want to go back to eating CHO.
        But had no choice, to experiment with CHOs. This is what works for me
        now. So like Robb said on his CHO three part series, calories do matter
        and to tinker.

        Thanks for this post and Robb’s CHO three part series from before.

        • says

          I’m honestly still tinkering too. Ketogenic just gives me rock solid energy, cognition etc. BUT, can’t seem to do the work output I need for grappling.

          • Cat says

            GAWDDD ROB!

            This is why I love you.

            Every time I take the advice of a ‘nutritional expert’, who seemingly has all the answers and a fool-proof plan, and that advice doesn’t work for me, I am left feeling pretty darn helpless because their ‘bullet-proof’ cure-all just didn’t work for me. It makes me just want to throw in the towel and say, f*** it. I’m broken.

            The fact that you’re still tinkering all these years makes me feel like we’re all stuck on the same paleo boat together. That no one has all the answers and only YOU can find out what works for YOU. YOU have to take responsibility for your own health.

            It’s empowering. You’re empowering Robb.

            This is why you are, and will always be, the FIRST person I turn to for guidance. Although I dearly love Mark Sisson, his failure to share his own vulnerability intimidates me and leaves me feeling helpless in the midst of all the contradictory evidence that us paleo folk are painfully aware of. Your failure to take on the ‘all-knowing-guru’ status makes me have so much faith in this way of eating/living, and I know your attitude towards all this is a HUGE reason why the paleo-movement has picked up so much momentum in recent years and shows no sign of slowing down anytime soon. I am eternally grateful.

            You better live forever damnit. I don’t know what I, my future children, my future children’s children, would/will do without you.

            Okay. I’m done being all mushy now 😉

  4. Mike B says

    Very well written, just wish that the need to write it all didn’t exist.
    If people would use the the organ that is encased in bone at the ends of their necks and apply a little critical thinking with the understanding that nothing in life is black and white and especially in human biology you would not have had to write this at all.
    I get it though, when people first find Paleo / Primal and it works they are afraid to change anything for fear that it won’t work anymore.

    Thank you for all you and Robb do.

  5. Ben says

    I think a lot of people, like myself, get too caught up in being a “performance whore” for no good reason, i.e. it’s not our profession. We assume that it doesn’t damage our health. Dr Perlmutter has done us all a great service by broaching a topic that is important when trying to individualize this stuff. After that podcast I for one have decided to adopt a more “primal” style of exercise instead of my typical beat down routine because my goal is health and longevity; performance is a distant second goal. Thanks Robb and team for thinking so much about this topic, and making yourself vulnerable to criticism. You’re my heroes!

  6. Ben says

    Also, I just picked up the 2012 publication of The Art and Science of Low Carbohydrate Performance by two PhDs, Jeff Volek and Stephen Phinney. Their bios are great and they seem like the perfect, quirky experts to have on your show to dig into this topic some more.

  7. says

    Excellent article! I found it very helpful. One of the things I’d like to see a discussion on is the evolutionary psychology and/or addictive aspects of carbohydrate intake.
    Dr. Richard Johnson talks about how we are essentially wired to crave nutrient-dense foods in his book The Fat Switch and I think knowing that about the nature of our minds is an important thing to consider when we’re attempting to live a paleo lifestyle.
    As a nutritionist, if I told a client they could never have leafy greens again they’d probably shrug and say “Okay, if that’s what’s best for me, no problem”, but tell them that they need to eliminate sugar and grains and there is a very real, very negative, psychological/emotional response for most people. I’d love to find some articles/info on what that’s about. Is it due to the addictive qualities of sugar? Is it due to impaired glucose regulation impacting our brain function? Is it about an evolutionary psychological wiring that causes us to prefer nutrient-dense foods? Is it about conditioned responses to high-carb foods, like breast-feeding and being fed ice cream as a reward or to placate emotions? Probably a combination of those, and likely a few more things we haven’t even uncovered yet. Any resources are appreciated! Thanks!

  8. Cat says

    Hey Rob! I have a quick question.

    Have you seen this BBC documentary?:

    I watched it the other day and found it interesting, but the part where they compare the incredibly calorically restricted man to the guy presenting the story left me kind of disturbed. Although the restricted men’s blood work was impressive compared to the average joe’s, he didn’t LOOK healthy. In fact, he looked weak, brittle, and about to fall over at any moment. I can not imagine living like that, day in and day out, no matter if it did give me a few extra years of life.

    My question to you is this, could years of severe carb restriction/ketogenic dieting leave us in this same predicament? Looking like complete and total a** with amazing blood work?

    I always associated attractiveness with health, which yes I know is not always the case, but this documentary has left me questioning if they are AT ALL correlated. I know you know the science of this stuff in and out like the back of your hand, but can I get your general impression of this documentary?

    Yes, I know this is kind of a vein issue, but I can’t help it being the 24-year-old female that I’m more concerned about looks than longevity at this point. But hey, if looks were all that I cared about I would just go under the knife, ditch paleo, and sit on my butt and eat fruity pebbles all day – I still want both.

    • says

      It’s a great question. I tackled some of this in part three of this series I wrote:

      it looks like the most severe cal restriction may only give us about 6 more years. Not an insignificant amount of time, but simple exercising gives us about 3. I think some occasional intermittent fasting is smart, a few forays into ketosis here and there are not a bad idea, but the hope I had of IF being an amazing middle ground offering better performance AND some life extension upsides is pretty unlikely IMO.

      • Cat says


        It just drives home the fact that I’d rather live for 80 high-quality/happy years rather than 100 miserable ones.

  9. Kevin Cann says

    This was a great article with good timing. I do not think the problem is the carbs. These diseases we are talking about are mismatch diseases. They are caused by placing our species in an unfamiliar environment. Low level systemic inflammation causes insulin resistance. This comes from making poor food choices, not getting enough sleep, not managing stress, etc. Carbohydrates such as root tubers and fruits have allowed our species to survive about 2 million years.

    We are wired to eat, store fat, and rest when we can. This was advantageous to the times when we had to hunt and gather our own food. The problem is we still have these evolutionary traits to store fat and be lazy with an abundance of supermarkets and fake foods available.

    I think Mark Sisson’s physical activity recommendations along with what Robb said above (a little IF, a little ketosis here and there, eating carbs to fuel activity…) is a great place to start. We still live in an environment we are not adapted to though. It is constant work with my clients because we come face to face with various life stressors and situations that are constantly changing things.

    The billion dollar question is how to account for these environmental pieces that we are poorly adapted. The article touched on these a few times sleep in a blacked out room, do APPROPRIATE amounts of exercise (Are we even truly adapted to intense activity?), do some active stress management stuff, and eat a real food diet. We know that there are positive health benefits to this stuff.

    To say its all in the carbs though is narrow minded. I would argue that if we could control for other environmental mismatches and ate carbs from fruits, tubers, and squashes that the carbohydrate intake may not matter much in overall mortality. Of course there is genetic variation amongst different groups and our paleolithic ancestors were not eating creamy mashed potatoes so the foods would have to more closely resemble those from the past and carb intake would need to be appropriate for each group.

    I don’t even know where I am going with this stuff, I just find it fascinating!

  10. says

    Beautifully written article, Amy! I find it so refreshing to hear both sides of the so called “story” on carbs. Dr. Perlmutter is fascinating and I respect the man greatly… but there’s no questions that two different people can process and “operate” carbs drastically different (my husband who is a Marine and naturally 5% body fat vs myself is a great example!)

  11. Maria says

    is it normal for my blood glucose to rise to 150 after a meal only of protein, fat and veggies? I’m not eating VLC, but I use coconut oil. I eat veggies, one/two servings of fruit and one sweet potato. Should I be concerned? Why does this happen? I though this “physiological insulin resistance” only happened to those who do VLC and have high fasting blood sugar. My fasting blood sugar is always 70.

  12. Kyle says

    Seriously, one of the best articles I’ve read in a long time! Taking the gigantic sphere of health and making it easily understood, sensible, and funny!!

  13. Lindsay says

    Hi, I’m a former patient of Dr. Perlmutter. While I agree with your points on the negative effects of carbohydrates, I’d like to say a huge FUCK YOU to you for calling Dr. Perlmutter’s patients, a group which includes myself, broken. I graduated USC summa cum laude in May with a 3.93 GPA, am excelling at a well-paid PR job and enjoy spending lots of time with friends and family each week. If that’s what you consider to be “broken,” then I’d like to know what you consider “intact.” Seriously, go fuck yourself.

    • says

      Lindsay, he is talking about people with severely compromised health. In other words, a diabetic’s endocrine system is broken. He’s not calling you mentally broken. Perhaps pay more attention to what he actually said.

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