March 15, 2015


Random finding (plus pi)

The best part of parenting (so far)? Helping your kids overcome things you struggled with. It’s at least in the top 5.

Read Time 6 minutes

The best part of parenting (so far)? Helping your kids overcome things you struggled with. It’s at least in the top 5.

Last Saturday my daughter came home from dance class—something she normally loves—and seemed upset. A bit of prodding led to the cause: a girl in her dance class told her she was “as fat as a hippopotamus.”  My first reaction (note to self: probably not the right one) was to laugh out loud, given that my daughter is probably in the 10th percentile of weight for her age. I’m worried she’s too skinny!

Of course I realized quickly the “facts” were irrelevant in this case. Her body habitus was moot. But her feelings were hurt, and as we all know this wouldn’t be last time someone said something to her—true or untrue—that would hurt her feelings.  I won’t go through the entire discussion we had, as I’m sure those of you with kids have already been through this, and those of you without kids probably aren’t worrying about this type of interaction.

I did, however, decide to tell her about all the people who dislike me and say mean things about me, usually things that aren’t true. She was shocked, “Like what, daddy?” I gave example after example. She was amazed—and relieved, I suspect—to know that she wasn’t alone and that I was able to shrug it off after temporarily being upset by it. I even told her about folks posting videos on YouTube specifically attacking me.

So, when our little talk was over she asked if she could see one of the videos I alluded to. I was a bit hesitant, if only for some of the language used when folks rant against my existence (if she’s going to learn choice 4-letter words in earnest, it should be from me after all), but I figured it was a good idea. She could actually see for herself that people say mean things about her dad and he’s still, more or less, ok.

Which brings me to the point of this quasi-post…

In searching for said YouTube videos, which I eventually found, I stumbled across two talks I gave last year which made their way online, unbeknownst to me.

In keeping with the current spirit of my co-op blog posts, below are links to the two talks.

Talk 1: Evidence for (and against) the dietary guidelines restricting saturated fat



This talk is an updated version of a talk I gave a few years ago and shared on the blog, in 2012 I think. Even if you watched the earlier version of the talk, if you find this question interesting—what is the case for restricting saturated fat (SFA) intake—it’s worth watching this version. I find this particular topic especially interesting because I think it highlights the challenge we all have, myself included, in setting aside bias when confronted with new information. (My friend Carol’s amazing book, Mistakes Were Made (But Not By Me) cannot be recommend highly enough for people who want to understand how cognitive dissonance wreaks havoc in even otherwise functioning societies.)

And contrary to what some (perhaps many) of you might think, I don’t believe this is a settled debate across the board. What do I mean by that (i.e., “across the board”)? Certainly in this presentation I try to make the case that the continually falling recommendations for SFA—from 12% to 10% to 8% to 5% of total calories—are not supported by convincing science. In fact, such recommendations likely do harm, courtesy of the “substitution effect,” i.e., people end up eating more of other things—namely, sugars and omega-6 polyunsaturated fats (n-6 PUFA)—that likely cause greater metabolic derangement.

However, some readers may interpret the data I present to mean it’s perfectly safe to consume, say, 25% (or more) of total calories from SFA. I realize I may have to turn in my keto-club card, but I am convinced that a subset of the population—I don’t know how large or small, because my “N” is too small—are not better served by mainlining SFA, even in the complete absence of carbohydrates (i.e., nutritional ketosis).  Let me repeat this point: I have seen enough patients whose biomarkers go to hell in a hand basket when they ingest very high amounts of SFA. This leads me to believe some people are not genetically equipped to thrive in prolonged nutritional ketosis.

In one particularly interesting case, a patient in self-prescribed nutritional ketosis presented to me with an LDL-P of more than 3500 nmol/L1i.e., more particles than could be measured by the NMR machine so the report simply said “>3,500 nmol/L”. despite feeling, performing, and looking great. Based on his through-the-roof desmosterol and cholanstanol levels, and a curb-side consult from the Godfather- I mean Dr. Tom Dayspring, I decided to try an experiment. You see, the logical thing to do in this setting would have been to start two drugs immediately (a potent statin to address the hypersynthesis and ezetimibe to address the hyperabsorption) or tell him to abandon ketosis altogether. But this patient was adamant about staying in ketosis given the other benefits, though obviously worried about the long-term coronary implications. So, we agreed that for a 3 month trial period he would reduce SFA to an average of 25 g/day (vs. about 75 to 100 g/day) and make up the difference with monounsaturated fat (MUFA).2We also reduced his omega-3 PUFA given very high RBC EPA and DHA levels.

So, on balance, he consumed about the same number of calories and even total quantity of fat, but his distribution of fat intake changed and he heavily swapped out SFA for MUFA.

The result?

His LDL-P fell from >3,500 nmol/L to about 1,300 nmol/L (about 55th percentile), and his CRP fell from 2.9 mg/L to <0.3 mg/L (and for the lipoprotein cognoscenti, both desmosterol and cholanstanol fell).

Pretty cool, huh? So, my point is this: while I believe the population-based guidelines for SFA are not supported by a standard of science I consider acceptable, it does not imply I believe SFA is uniformly safe at all levels for all individuals.

Some of you may be wondering about me. It turns out I’m in the group (recall: I have no idea how large or small this group is) that seems to do well—at least by the tools we have available to assess risk—with large amounts of SFA in my diet, if and when I elect to. Even when I was in ketosis, eating 4,000 kcal/day (literally getting 40 to 45% of my calories from SFA alone) my biomarkers—cardiovascular, insulin resistance, inflammation—were excellent. Better than they ever were or even are today. Though, my point still stands: there are some people who do not appear able to safely consume massive amounts of SFA.

One last point I’ll make on this highly charged topic. I realize there is a contingent within the LCHF community who argue that traditional biomarkers of coronary risk—such as LDL-C or its superior cousin LDL-P—“don’t matter” if one is on a low carb or ketogenic diet. Maybe they are right. I guess time will tell. But I am not convinced, at least not yet.  As a doctor I can’t look a patient in the eye and tell them a sky-high LDL-P is ok because they don’t eat carbohydrates. So if you’re following such a diet, and your LDL-P goes through the roof, I’d urge you to consider a variation of the diet.

(Note: If you post your NMR results, please understand I will not comment on them.)

Talk 2: It was the best of times, it was the worst of times—the tale of the U.S. healthcare system


This presentation has nothing to do with nutrition but is, nevertheless, a topic I’m pretty obsessed with: how do we achieve cost containment on healthcare in the United States? (Sorry non-U.S. readers, but we have a bigger problem right now, so I’m focusing on ours over yours!)

This is a pretty controversial topic, so before you jump down my throat, try to sit through the entire talk, especially the parts where I frame the question as one of optimization. Most problems that have been heavily politicized suffer a common problem: they fail to distinguish between what is desirable in a resource unconstrained world (e.g., free health care for everyone that provides perfect care) and what is plausible the real world (e.g., some combination of features, but not 5 starts across the board).

Hope you enjoy the departure from the usual topics.

Pi Day

The math geeks in the audience will appreciate that yesterday, March 14, 2015, represented a very special variant of pi day. Normally, March 14 represents pi to 3 significant digits, namely, 3, 1, and 4 (i.e., 3.14). Yesterday, however, being the pi day in 2015, was especially cute, because it advanced two more significant digits, 1 and 5, via the year (i.e., 3.1415). If you’re a watch geek, in addition to being a math geek–yes, I realize this is not a huge club–the beauty of a perpetual calendar (a type of watch that shows time, month, date, and year inclusive of leap years), made it a really fun day! Why? Because at 9:26 and 54 seconds you found yourself at the following place in time: the 3rd month, 14th day, 15th year (of this century), 9th hour, 26th minute, and 54th second, that is, 3.141592654–pi to 10 significant digits!

After capturing this wonderful moment in time, I sent the picture, below, to my watch mentor (also a math geek; yes I just wrote the words “watch” and “mentor” next to each other). He loved it, but his response was priceless: “Peter, don’t ever show this to any woman you have the slightest interest in….check that, don’t show it to any woman period. Pretty cool though. You are right. I dig it.”

Good thing my days of trying to impress the ladies are far in the rear view mirror.

Parting shot: I did a follow up podcast with Tim Ferriss a few weeks ago. It’s episode #65 which is available on iTunes. This was my first time doing the strange format of just talking by myself. Feedback appreciated if this should morph into something I do quasi-regularly on the blog.


Pi on abstract background with about 3500 decimal digits by Nicolo Canali De Rossi is licensed under CC by 2.0

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  1. Hi Peter,

    New follower here from the UK.

    I’ve searched you site and I wonder whether you have any detailed talks on why some people seem to have more success becoming lean (from an aesthetic perspective) on a Carb Cycling or Timed Carbs style diet than on Ketogenic Diet?

    I’ve been on Keto for a few months and I notice some others having more joy despite eating more carbs.

    Apologies if this has already been answered or if it seems like a silly question.

    • Zak,
      I am new here too. I posted a comment 4 days ago, and on my computer, it still shows as waiting for moderation. I was wondering if you can see my posting just above yours or not? Thanks.

  2. Hi Peter,

    With regards to Tarek’s comment above about fasting and ketogenic diet, just to add that the fasting Tarek referred to is even without water or any other fluids. It comes to around 18 hours in UK per day.

  3. Have you tried out, or taken a good look under the hood of, Metabolon’s Quantose IR testing? They are right down the street from where I used to work.

  4. You want to have a look into that:

    “Similarly, most peoples’ bodies will turn to blobs if they eat almost any carbs (45%) or almost any fat (39%). This is why the holy wars between paleo and atkins people are so intense. They don’t realize there really are at least two correct diets to belong to… for two distinct classes of people. Researchers have found that people who do the diet that’s matched to their genotype (for the 5 best markers scientists know of today) can lose weight 2.5x as fast as those on the opposite diet. Stanford is replicating the study right now.”

    Wondering how much credence you’d give to this piece of evidence.

  5. I have noticed that going on a low carb diet got my libido to zero!! what are your thoughts and experience around libido and erectile dysfunction on a low carb diet?

    • Foods like beef, fish, oysters, eggs with extra fat from coconut / olive / butter should actually boost your libido. On the other hand if you are reducing calories (i.e. low carb but also low fat) and losing excess fat your body may naturally lower the libido. So eating good food but also eating enough of it should work.

    • Got to agree with Martin on this one. And Mark Sisson. Eat more saturated fats. Lift heavy things. DO some strength and speed exercises to the maximum. Work out around other men when you can. Alll those are shown to help T, and libido.

  6. Hello Peter!
    Do you have an opinion on the social implications of a ketogenic diet? I am asking, because the media tends to report a lot on overfishing, antibiotics in raising livestock, methane emission by livestock, long-distance food transport/CO2 emission. Which types of foods are healthy and environmentally acceptable in your opinion? Are Avocados and Coconut oil the way to go?
    Since you have a very differentiated opinion on many health related topics and since your are a regular reader of the NYtimes (according to your twitter profile), I guess you have already thought about the aforementioned. I would love a podcast, post or comment on that matter. Thank you very much in advance.
    Kind regards and thank you for the great blog,

  7. Peter, maybe because the kind of work you’re doing is so awesome, I keep finding myself pushed to share stuff that may help you along the way, plus thinking about themes around it. Below a bunch in no particular order of importance:

    1) Watching your TED Talk I realized something: you are one of the very few people I know who overcame attitude polarization (a type of confirmation bias) and got to the point of publically saying, in the middle of one’s successful profession, “you know, maybe I’m wrong about what I’m doing and my beliefs”. And instead of going to the opposite side, you paused and said “actually, we don’t really know what’s going on and we should stop and try to find out first”.

    Please accept my deep respect for your attitude.

    2) Recompress your blog jpgs or convert them to gif. Two advantages: you save bandwidth money right away, and you lower your bouncing rates (higher loading time drives more impatient people away). You can reduce size with no loss of quality at all. Many software for that depending on your OS, also online tools.

    3) You said people normally get into nutritional ketosis in some weeks after they started for the first time, but you, on the other hand, seem to get back to it in a couple of days after a desert binge. Would you say NK works a bit like a muscle, in the sense that the more the body is used to getting into (or staying at) this metabolic route, the faster it is able to click back into it when starved from glucose?

    4) In some comments in some post, and maybe by you too, I saw criticism about studies in mice, as if implying that they are meaningless to extrapolate data to humans. My impulse wasn’t to join and laugh and agree. Up to now, I’ve always thought that although you can’t directly extrapolate mice results to humans, they should be close enough, because after all we are evolutionarily very close to mice.

    Two points from this: one, are mice results that bad, really? Is a clinical trial in rats worse than an observational study in humans? Two, and here I want to tease you with an idea:

    I’ve watched TED talk from “Barbara Natterson Horowitz: What veterinarians know that doctors don’t”. Long story short, she started noticing enormous parallel between animal and human diseases, and found that many of the “discoveries” we make to treat humans had been already discovered by vets years before. And she started looking into vet literature for hints of how to translate that to humans, and to put vets and human doctors in contact, which generated a lot of insights and new treatments.

    What is it that we already know about animal nutrition, obesity and IR in animals as well as their treatments that could translate immediately for humans and we are massively overlooking it because of our views of vets as “inferior” and because we (mistakenly) think of non-humans animals as being a world apart from humans?

    I recommend you watch the talk and maybe contact her. And yes, I’m suggesting (as she would) that you talk to selected vets or go to a veterinarian convention, raise your hand, and say “Hi, folks. I’m looking deep into human nutritional and insulin resistance, and we need all the help we can find to solve this problem. What is it that you, vets, already know about this problem in animals, how they vary between species, and how do you treat it?”

    If you think about it, it’s not half as crazy as it first sounds, and may give you insights, good questions and good answers that you may not have had otherwise.

    All power to you.

    • I found like talk by Dr. Layman very helpful.

      I’m a 60 your-old man with inconsistent exercise habits/schedule. I’ve been trying Dr. Layman’s suggestion of getting 30g of protein per meal, and I think it helps.

      (For example, I’ve been injured for the past month and not able to do push-ups. Yesterday I dropped down and dis a set of 40, which is the same number I was doing before I got injured. I’m just a sample of one, but I buy his suggestions about protein.)

      RIchard S.

  8. Peter,

    How valuable is the TG/HDL ratio as a proxy for LDL patterns?

    For example, my doc doesn’t think I need an LDP-P or ApoB test, even though he’s concerned about my TC and at 250 and my LDL at 166. On a LCHF diet I’ve dropped my TG/HDL ratio to 1.6 (111/66), so I’m thinking (hoping) my LDLs are of the fewer, larger type.

    Do you think people should use or rely on the TG.HDL ratio? Or should we all get tested for LDL particle counts?

    (I’ve also had high Lp(a) when not on statins. Don’t know how much that supports a “do the particle test” answer.)

    Thanks for all you do!


  9. Dr. Attia:

    Great to see a terrific new post! Your reference to cognitive bias and your friend’s book recalled Nobel-winner Daniel Kahneman’s work (“Thinking Fast and Slow”). His research on judgment and decision-making errors is fascinating and indispensable.

    “Ego depletion” is one research area. Various methods are used, but essentially, subjects engage in rigorous mental effort for prolonged periods. Following exertion, some consume meal or glucose-containing beverage. Others get nothing or artificially sweetened drinks. Researchers found that subjects given glucose overcame “ego depletion” and made different decisions. Other subjects remained “depleted”.

    Wondering if you’re familiar with any of this and what you make of it. I’m not an NK dieter but foreswear added sugars and refined carbs. Makes me wonder if avoiding both added sugars AND an all-out NK approach leaves one particularly susceptible to this “ego depletion” phenomenon — Whereas true-blue NK dieters and unopposed to sugary drinks might more easily overcome it.

    Thoughts? Might make for an interesting, peripheral follow-on experiment at some point, if nothing else.

  10. Dr. Attia,

    I would love to attend a live lecture/talk. Do you post a speaking schedule or is there somewhere I can buy tickets?


  11. Hello , do you think that it is possible to play professional tennis on ketogenic diet ?? With all bursts of energy and need for quickness. I am a tennis player and I have hyperinsulinemia and I really want to try keto .

  12. I’m starting to see more articles and research swinging the pendulum towards carbs (e.g. carbs made us smarter as a species), as crazy as that sounds. To be honest, I’m starting to think that health may really just involve eating less food (regardless of its composition), and maybe with that, periodic fasting. Perhaps the low-calorie acolytes of the last decade were on to something.

    • Perhaps, though just how much caloric restriction (CR) is a question and whether the benefits of longterm CR are greater than or less than the longterm risks (I think the in the longrun the risks are greater of prolonged CR). But the more interesting question may be around IF or other CR-mimetics.

  13. I just saw this ‘metabolic ward’ study published in Cell Metabolism, and I wanted to make sure you saw it too. I wish they had implemented a truly low-carb diet (<50g/day) to do this comparison, and they tried to project such results via mathematical modeling, but it's still worth a read. I'd love to know your thoughts.

    Hall KD, et al. 2015. "Calorie for Calorie, Dietary Fat Restriction Results in More Body Fat Loss than Carbohydrate Restriction in People with Obesity." Cell Metabolism; ePub ahead of print.

  14. Have I missed it somewhere, or has the question already been asked?: have you read the NIH study that’s being characterized by the press as a vindication of low-fat diets, and, if so, what’s your initial reaction to it? I read Kevin Hall’s article in Cell Metabolism and noticed the low-carb diet wasn’t a very low carb diet, and was very short-term. I gather that most of the conclusions about the long-term effects were based on computer simulations extrapolating forward. That said, if their methods were sound, it was a surprising finding. I did notice that the lipid profiles were better for the low-carb group if you think high HDL and low triglycerides are more important than low LDL. I’m also intrigued that Kevin Hall is also one of the investigators on NuSI’s Energy Balance Consortium.

    • “I read Kevin Hall’s article in Cell Metabolism and noticed the low-carb diet wasn’t a very low carb diet, and was very short-term.” You can say that again.
      “I gather that most of the conclusions about the long-term effects were based on computer simulations extrapolating forward.” Correct. You know what George Box said about models, right?

  15. dr attia,
    hi, i absolutely love your stuff,
    i’m an e.r. doc, making my way back from 9 years of diabesity, now getting well thanks to low carb/high fat / intermittent fasting.

    i have fasted as long as 94 hours so far, on bone broth and water, and in three months – have dropped 30 lbs, and lowered Hgb-A1c from 9.0 to 5.6, and dropped hs-CRP from 3.6 to 1.5, and come off of insulin, actors, and metformin. 🙂 and feel GREAT.

    friday, i am going to the sports physiology lab, at the local university, for a modified vo2-max testing
    a vo2-MIN testing, if you will. (they don’t have the hood thing / isolation room for a 24 hour measurement.

    instead of pedaling the bicycle, i’m gonna lay comfortable and still, on a gurney, and try to NOT think about anything.
    it will be a short 30” assay, after 15” of equilibration,

    goal is to get a rough idea of what my (currently) generally sedentary kCal/day expenditure is.
    this will kinda just count the calories of breathing, heart beating, blinking, etc.

    to that, i can then add some data from the fitbit thing my wife bought me for Christmas, but i have never used, till tomorrow.
    and also add in estimates of calories from time x distance walked, cycled, etc.

    just wanting to get a reasonable of where my general caloric needs are for intake, since i still have a lot of calories stored from years gone by that i want to get rid of

    would it be better to approach this fasting? or fed?
    for best applicability?

  16. Hello Peter, since I discovered you I can only describe it as amazing! Thank you for what you do and I trust that one day the world will be able to benefit.
    My question/ask of you is with regards to the use of statins for primary care/intervention to prevent CVD or CHD (I presume these two terms are synonymous). I believe the data leading many doctor’s belief that taking statins by those with ‘risk factors’ is preventative toward CVD/CHD is at least highly questionable and potential wrong. What is your view? Thank you.

  17. If this topic has been discussed elsewhere I would be happy to be pointed in the direction of good reading material.

    I followed a very strict ketogenic diet for about half a year and then continued a semi low carb diet for the last year. One of the most shocking changed I have observed is about hunger. I don’t get hungry in the same way as I used to. When I ate Honey Nut Cheerios and Mountain Dew for breakfast, I could not focus by the time 11:00 came around because I knew lunch was coming. One and a half years of low carb later, even after a relatively high carb breakfast (e.g. oatmeal), I can skip lunch and still function. Something has fundamentally changed with my body

    FYI I been lean my whole life and my weight did not change through experimentation, just hunger.

    So my related questions:
    What biochemical mechanisms regulate hunger?
    What part of my metabolism changed before/after this diet experiment?
    Why could I not focus on math when I used to eat loads of sugar?

    p.s. I am an undergraduate in biochemistry so this stuff if fascinating.

  18. You mentioned in one of your Podcasts that post-menopausal women are in their own class when it comes to weight loss. I have read most of the major books on the subject of Ketogenic diets. There is lots today about the experience of athletes and obese people. But, there is almost nothing about the unique struggles of many, many women who can’t lose much weight once they go over 50 and their hormones change. Where can I find more information?

    Here is my case: I have been on the Atkins diet for 1 year. I lost 22 pounds in 6 months and got to a normal BMI. Then the weight loss stalled. I was 20 pounds from my weight 5 years ago prior to a gelato and pasta binge in Italy. In the past year, I have had no sugar and no starch and never more than 35 net carbs. I have tracked my calories off and on usually staying between 1500 and 1800. At 5’10”, this is not a lot of food. I have exercised consistently but only moderately. I got just got a Ketonix so I am tracking that too. It measures that I only produce moderate Ketones. Would love it if you posted more on the what you refer to as a unique class of dieters: post-menopausal women. Thanks. Your blog has been a big help.

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