September 10, 2014

To Carb or Not to Carb: That is NOT the Question

The question is: Why are we still even having this debate? (Or is it a discussion?) Is it really that difficult for folks to accept and/or agree that some people thrive on lower amounts of carbohydrate, while others feel their best with more? I’m not sure why the controversy continues. It is well established that there is no absolute human need for dietary carbohydrate. Let me say that again: there is no human dietary need for carbohydrate. Just so we’re clear, this doesn’t mean glucose isn’t needed for plenty of biochemical pathways and physiological mechanisms in our bodies. It means only that our bodies can get the glucose they need by means other than us ingesting it.

That being said, very few people are saying that because there is no human dietary requirement for carbohydrate, we should all be on a ketogenic diet from birth until death, every single one of us, no exceptions. (Not even Jimmy Moore, the keto man, himself, is saying this. [See point #3 in this post.]) If anything, it seems to me that the main messages being put out make it clear that people need to find what works best for them, and that even if/when they do find it, it might change over time. (See: Kelsey Marksteiner's 3 step process to determining your ideal carbohydrate intake; and Chris Kresser's 7 things everyone should know about low carb diets.)

See also Robb Wolf's Thoughts on Carbs & Paleo: Part 1, Part 2, and Part 3. (And maybe even this one, written by yours truly.)

The macronutrient (and micronutrient!!) numbers that work best for your wife/brother/boss/next-door neighbor/favorite internet health guru might not be best for YOU. As Robb Wolf might say, “Shocker!”

I guess it all started with Laura Schoenfeld's post, Is a Low-Carb Diet Ruining Your Health? Like I explained here, I really have no problem with the article itself. It's only the title I didn't like so much.

Warning: This is a rant. It is not an especially politically correct one. I am telling it like it is, or, at least, like I think it is. You have been warned.

Second warning: Most (but not all) of what appears below is speculation and informed reasoning on my part. There is some science, but I'm not using a ton of PubMed links because, well, frankly, peer-reviewed scientific literature leaves a lot to be desired these days. I know; I do freelance writing for a supplement company some of you might be familiar with, and in the course of my work, I do a lot of digging on good ol' PubMed. It ain't the gold mine it's cracked up to be. More on that some other time. Bottom line: if you think this post is useless because of its lack of copious citations, you know how to delete the email or close the window. 

To the rest of you, happy reading.

If a low-carb diet isn’t working so well for you, that doesn’t mean you’re “doing it wrong.” Maybe you need some more freaking carbs! And if a high-carb intake is making you physically and psychologically miserable, maybe you’re not one of the anointed who do well with liberal amounts of potatoes, white rice, and plantains. Why is it so hard for people to wrap their heads around this mindblowing and stunning concept?

There is no one perfect diet for everyone. I’m as big a fan of the work of Staffan Lindeberg and Vilhjalmur Stefansson as the next gal, but if I hear one more freaking thing about the Kitavans or the Inuit, I’m going to lose it. Frankly, references to these two groups are beginning to strike me as lazy. The Kitavans thrive free of modern chronic illness on diets including lots of yams, tapioca, taro, pineapples, papayas, and guavas? Fine! Awesome! For the Kitavans. The Inuit maintain excellent health on diets high in marine flesh and blubber, with much lower amounts of vegetables and fruits than we could possibly imagine is “healthy?” Fabulous! This is great!  For the Inuit. For me? Whoop-dee-doo! I am neither a Pacific Islander nor a dweller of the Arctic. I’m not saying that, ergo, those two population groups have absolutely nothing to tell me about human physiology and metabolism. I am saying only that these people might thrive on their particular diets because they are those particular people! Why is this so freaking hard for people to wrap their heads around?

Frankly, I don’t give two hangs that the Kitavans can consume the majority of their food intake as fruit and starchy tubers. If I did that, not only would I likely weigh at least twice—if not three times—what I do now (and no one in their right mind would hire a nutritionist of that size, so I’d also be out of business), I would also likely keep eating them, as these types of foods are very difficult for me to stop eating once I’ve started. (Yes, for me—for me—even these types of non-grain carbs are tough to walk away from after a reasonable amount.) And maybe there’s someone out there from a Pacific Island where their ancestors wouldn’t know a grazing dairy cow or sheep if it squirted milk into their eye. Would we presume to tell that person that there is no human dietary requirement for carbohydrate, so they should give up their mangoes and get all their calories from animal protein and fat instead, being especially careful to include lots of cheese? 

Am I the only one who thinks this whole thing is madness?

There’s so much coming out now about epigenetics, single nucleotide polymorphisms, the gut microbiome, and other inputs, systems, and interactions that we scarcely could have imagined a century ago. Why do we seem to be ignoring the role these play in bioenergetics and overall health? Why is it so difficult to fathom the possibility that darker skinned people might need more sunlight because their DNA has evolutionarily programmed them to “expect” much more sunlight exposure than, say, a fair-skinned, blue-eyed Norseman? Why is it equally hard to imagine that people whose ancestors lived for thousands of years in coastal areas might have a higher dietary requirement for pre-formed EPA & DHA, since, again, maybe their genes have come to “expect” that they would consume plenty of marine life? And inland peoples might—just might—be more efficient at making the conversion from alpha-linolenic acid (ALA) into these longer-chain unsaturated fats, because they were not consuming as much seafood? (Something I hypothesized here.) I’m not saying this is the way it is; only that it’s possible. And if it’s possible, then for goodness sake, can we PLEASE stop using the freaking Inuit and the freaking Kitavans to argue opposite sides of the spectrum? Very low-carb, versus very high-carb? There is a huge spectrum in between those approaches. What the health of those two groups tell us is that the human race—possibly depending somewhat on geographic ancestry and ethnic extraction—can thrive on a wide variety of macro- and micronutrient intakes, but those macro- and micronutrient intakes need to match up with said geographic ancestry and ethnic extraction. They do NOT tell us that everyone, across the board, will thrive on starches and fruit, or that everyone, across the board, will thrive on seal meat and oolican grease. Am I the only one who sees the ridiculousness (and UNproductiveness) of otherwise intelligent people reducing the defense of their stance on carbs down to Arctic versus South Pacific? Jeez Louise.

Please, please tell me it’s not impossible to wrap our heads around epigenetics and single nucleotide polymorphisms (SNPs). We already know pretty darn well that some people need a little boost in the methylation department, while others actually seem to over-methylate. (Listen to this awesome episode of Kiefer’s BodyIO podcast for more on this.) So why is it so hard to understand that the same kind of polymorphisms might affect the efficiency of enzymes involved in lipid metabolism, desaturation of ALA to EPA & DHA, starch digestion, and more? Some people have more copies of amylase genes, some have fewer. Some people are homozygous for the Ɛ-4 allele of the apolipoprotein E gene (a.k.a. APOE4), others aren’t. These are the kinds of things that can affect what kind of diet someone is best suited to. Robb Wolf likes to joke that we are not beautiful, unique snowflakes, but the fact is, it kind of looks like we are!

I’d say that one thing we do have in common, however, is that we’re all basically mutts at this point in evolutionary time. Most of our ancestors were quite the little swingers, if ya know what I mean. From north to south, east to west, Atlantic to Pacific, Old World to New World, one thing these people were doing was sleeping with each other like crazy. Most of us are a conglomeration of races and geographic origins. Even if you can trace your grandparents back to whence they came, what about their grandparents? And those grandparents’ great-great-grandparents? By the time you figure out who begat whom, you’ve probably circumnavigated the globe a few times.

Very few of us are purebreds. If you can trace your lineage back to the Mayflower and then some, back many, many generations, congratulations. (And when are you inviting me for doubles tennis followed by cognac and dinner at the country club with Muffy and Bo-Bo? Oh, wait…do they let Jews into those places now? Yikes!! See? I told you this would be politically incorrect. You were warned.)

My point is, I think the reason it’s so difficult to pinpoint the things that will make any one specific person live a lifetime of robust physical, psychological, and cognitive health, free of chronic pain and premature degeneration, is that we can’t be certain of what’s going on inside us. We have a pretty good idea of the overarching concepts, sure. But what about that methylation issue? What about the vitamin D/latitude/skin pigmentation/Naked ape hypothesis? (Or is it a theory by now?) What about the number of copies of amylase genes? And if people do differ in something like number of copies of amylase genes, who’s to say we don’t also differ in, say, copies of the genes for acetyl-CoA carboxylase, or pyruvate dehydrogenase, or fatty acid synthase, or phosphoenolpyruvate carboxykinase (a.k.a. PEPCK)? (Hehheh; that last one was just to impress you with my biochem skillz.) These are all enzymes involved in the metabolism of various energy substrates. And if we do differ in the amounts of these factors in our genome (and epigenome), then it is absolutely plausible that people really DO thrive on different amounts of carbohydrates and fats. And it is also absolutely plausible—if not flat-out likely—that the reason some do well on higher carb, and some on lower carb, is that their bodies are wired to be more efficient using certain substrates than others. Those fancy-sounding enzymes I mentioned a minute ago? Differing numbers of copies or polymorphisms in the genes that code for the final enzyme proteins could definitely influence how efficiently/effectively someone’s body converts glucose into fats (de-novo lipogenesis), or how easily they can create glucose from amino acids, lactate, and glycerol (gluconeogenesis), and how easy it is for them to break down glycogen into glucose. (NOW, someone, please, I dare you, tell me it’s all about caloriesGo ahead, I freaking dare you.

So there are athletes who can do Ironman triathlons in a ketogenic state, and there are people who practically fall apart until they add in a post-workout sweet potato. (Yes, I’m well aware of the notion that people who don’t do well on low-carb might just be under-eating altogether, but tell me you don’t think this other idea I’m putting forth here might also play at least some role. Yes, a lot of the women who claim their thyroid died, or their adrenals went to sleep are likely just eating 1200 freaking calories and thinking that’s enough, but I also think there are other people who are eating enough, and who just plain don’t do so hot on LC. And maybe this is why.)

For the very same reason—polymorphisms and epigenetics—one person might need more B6, iron, or vitamin A than the next guy. And someone else might need more manganese, chromium, or riboflavin. Ya get me? (This is what I mean when I keep talking about micronutrients. You do know that in order to actually do anything with the macros [protein, fat, and carbs], we need vitamins & mineral as enzyme cofactors, right? Try making EPA & DHA from ALA without biotin and B6, for example, or converting T4 to T3, the most bioactive thyroid hormone, without selenium.)

So I don’t think it’s so much that low-carb diets or higher-carb diets are “good” or “bad.” Again, to paraphrase Robb Wolf (as it seems I am loving to do today, but what can I say; he’s a pretty damn intelligent guy), who are you, and what are you looking to do? I guess maybe the problem is that, in 2014, many of us don’t know who we are, evolutionarily speaking. My grandparents came from Poland and Russia. Fine. Swell. Pierogies and vodka for life! Um, not so fast. What about their grandparents, and their insert-twenty-greats-grandparents? I’m also Jewish, so, presumably, at some point, I had ancestors in the Middle East. Sweet! Olive oil and figs for life! See? What-evs. Just pass the bacon. (Jewish, but not kosher. And thank goodness; my mother makes a mean pork chop.)

So why are there so many people out there so debilitated in so many ways? Their skin is mottled, their bones are crumbling, their minds are foggy, their vision is blurry, their energy levels are tanked, they can’t sit still and learn, they’re too anxious/depressed/fearful to leave the house and can’t hold down a job, their teeth are rotting, their hearts are failing, their livers are engorged with fat, their pancreases have called it quits. I could go on.

I believe—and of course I am not the first to postulate this; I am merely reminding everyone—that it is the MISMATCH between our genes (whatever they are now, and wherever they were evolutionarily shaped) and the environment we are exposing them to. Perhaps someone who would thrive on low-carb has been brainwashed convinced by the low-fat “thing” of the last forty years, and their health and quality of life has suffered for it. And on the flipside, perhaps someone who would feel like a million bucks with a more liberal carb intake has been hypnotized by the keto crowd, and is now too scared to eat a red bell pepper, for cryin’ out loud.

And of course, all this SNP/epigenetics/diet talk doesn’t even address the other can of worms—the enormous, epic, Costco-on-steroids-sized can of worms that is all the other factors that affect epigenetic switches and how our bodies process fuel substrates and micronutrients. Factors like, oh, I dunno, sleepphysical movement, fresh air, time in green spaces and/or near fresh water, getting daylight when it’s daytime and darkness when it’s nighttime. And factors like not sitting behind the wheel of a car or in a chair in a cube with our aggravation and stress levels regularly rising to degrees our ancestors were exposed to only intermittently, say, on the heels of a charging animal.

So I agree with what Jimmy Moore said in point #5 of this post: Even if we “all” are born with a tolerance for a higher carbohydrate intake (and I think it’s clear by now I don’t think we all are), by the time some of us are in our 30s, 40s, 50s and beyond, we have incurred so much metabolic damage from decades of combining a high grain, sugar, and just plain crap diet, devoid of nutrient density, with being sedentary, stressed out, and sleep deficient, that we just might be permanently unable to tolerate the same amount of carbohydrate as someone who spent their childhood and early adulthood eating and living in such a way as not to derange their liver and pancreas to the point where a lower-carb diet really is the only suitable option for the long term. (And please note, I say lower-carb because I am not necessarily implying ketogenic levels here. Sometimes that’s warranted, sometimes not. Unique snowflakes, remember? ) Taking things a step further (as if I needed to), what about the carb tolerance any of us is born with? They're finding out more every day about just how much a pregnant mom's hormonal and nutritional state can affect her offspring for life. How stressed is she throughout the pregnancy? Is she iodine sufficient? How is her blood glucose management and fatty acid status? How about her vaginal microbes? Is she delivering that way, or having a C-section? All of these things can affect the child long-term. So yes, I think some of us actually are born with a lower carb tolerance than others. (Not to mention a propensity toward all kinds of health issues in childhood and beyond.)

I believe there are plenty of people who can enjoy rice, potatoes, beets, fruit, and even bread and pasta. (Yes, gluten! I said it! Oh-em-gee!) And these people will experience a long, healthy life. But I also believe there are people whose bodies are no longer capable of efficiently metabolizing carbohydrates over a certain threshold. And you know what? The people in that first camp might find themselves in the second one at some point in the future. Maybe sleep, or stress, or activity levels, or something we don’t even know about yet, will affect things, and what worked like a charm at 35 years old utterly fails at 65. (Again, “Shocker!”) And vice-versa: people who feel they are very sensitive to carbs might find that if they alter their gut flora, or lower their stress levels, or get more sleep, or build more muscle, that they can safely consume far more carbs than they thought.

Oh, man. Believe it or not, I have more to say, but I’ll end here for now.

Until next time…

Do you have any thoughts? Am I completely off my rocker here? Should I put on a raincoat and brace myself for the tomato onslaught, or can I hold out hope that I have kindred spirits out there, who can see and accept that this is all a lot more complicated than we give it credit for, and injecting some calm reasoning into the discussion is a good thing?

Remember: Amy Berger, M.S., NTP, is not a physician and Tuit Nutrition, LLC, is not a medical practice. The information contained on this site is not intended to diagnose, treat, cure, or prevent any medical condition.


  1. I think most of us are completely lost about listening to our bodies whether what kind of nutrition, exercise or other lifestyle factors are optimal for the time being. So, it is like a religion to hang on to something like certain carb quantity as we do not really know what is optimal for us. Why do not we find out? We wish to get it handed to us like genetic or other laboratory testing and not by self experimenting which is much better as our lives are changing all the time.
    You are a great writer and obviously an excellent nutritionist. However, we cannot afford to hire you to feed us, decide our other lifestyle factors and write down our feelings then tell us that this is optimal for the time being. What other excuses would you like to read? So, we are supporting our gurus and wait for the better motivation day.

  2. Please continue on. This is getting interesting.

  3. Please define epigenetics before you all go on giving it some magical property.
    Wiki: Epigenetics is the study of changes in gene expression caused by certain base pairs in DNA, or RNA, being "turned off" or "turned on" again, through chemical reactions.
    My definition: "The ability of the organism to rapidly respond to environmental triggers that can switch between metabolic responses that have been evolved in the past. In the early industrial revolution the winter time color around London turned from snow white to soot black. A moth specie was observed to suddenly become black. Not enough evolutionary time for this. The black environment revealed the pre-evolved color change ability of the moth. So we come with an operating panel where different generational responses can be programmed. If a sudden cooling of the earth happens and it occurs long enough a get-fat-quick evolution takes place. If this happens repeatedly, evolution evolves a very clever fast response mechanism.
    So I disagree with a popular notion about the in-heritability of what we are seeing.

    1. Xogenisis, I accidentally deleted your other comment. Please re-submit it if you can. It was a good one! If you need the text, I can send it to you. Pls email me directly if you want. (Use the contact form on my blog.) Thanks!

    2. I accidentally deleted this comment from Xogenisis. Here it is:
      The basic facts. The health of a nation has been ruined by decades of consuming a macro nutrient ratio that is unhealthy for the majority of us. Most of us are metabolically damaged. Other factors are contributing of course but any discussion of how many carbs must account our state of health. How badly are you damaged and what should you do about it? For most of us it is no longer about what is a normal diet or what is the normal range of carb intake for a healthy human, but radical reduction as a medical necessity. Go way down on the carbs way up on the healthy dietary fats and keep protein intake moderate. Over time you may completely repair your biological mechanisms. After 15 years I am almost there. The food supply is now contaminated compared to my grandmothers early years in the 1880's. She ate raw milk and pastured animal foods on the one hand and plenty of grains and bakery products on the other. In the 1940's and 1950's I could still do that. The average American in my grandmother's generation looked like stick figures compared to us today. They had the advantage of antibiotics to avoid deadly killers and not the disadvantages of our fear of fat. Let's be realistic. It's not about what is the perfect diet for a normal healthy group of humans - this is not us.

  4. It seems that more people are accepting the idea of that one approach or a few dietary/lifestyle approaches are not necessarily appropriate for each person, or for the stage of life that a person is at. Try something and if it works, stick with it. If it stops working, try something new. To add to the mix, is a thought that we may be biologically inclined to natural patterns of food availability that follows the seasons, and that our bodies are confused by the availability of certain food types all year long, leading to health issues. It's pn;y really in the last 20 or so years, that one can expect to have year round access to cheap regular foods (such as apples) and exotic food (such as avocados) coming from all over the world. I can recall growing up that getting fresh fruit at Christmas was still a treat. (I'm not that old, but then again maybe I am...) Just a thought.