Evidence that Gut Bacteria Affect the Brain

Some of the most important unknowns about diet and health center around the effect of different foods on one’s gut bacteria—also called the gut microbiome. Different types of gut bacteria like different kinds of food, so what we eat affects which types of gut bacteria flourish and which types of gut bacteria wither away.

The best types of gut bacteria do part of the processing of food and can serve as a buffer between problematic aspects of food and the intestinal wall. And the worst types of gut bacteria can themselves produce unpleasant chemicals. And even if a type of gut bacteria is neutral in and of itself, if it crowds out the worst types, that is a big service. So it matters which types of gut bacteria are flourishing.

So far, the one set of recommendations I have discussed that are heavily informed by thinking about gut bacteria are those I discuss in “What Steven Gundry's Book 'The Plant Paradox' Adds to the Principles of a Low-Insulin-Index Diet.” And I talk about evidence that eating sugar causes bad gut bacteria to thrive in “Anthony Komaroff: The Microbiome and Risk for Obesity and Diabetes.”

Possible mechanisms involving gut bacteria should keep you from being complacent about the effects of diet on your health. David Kohn’s Atlantic piece, “When Gut Bacteria Change Brain Function,” points to likely effects of gut bacteria on the brain. Here are some key passages from that article, shown by indentation, with my characterizations interleaved without indentation:

By now, the idea that gut bacteria affect a person’s health is not revolutionary. Many people know that these microbes influence digestion, allergies, and metabolism.

Putting B. fragilis bacteria into a mouse model for autism reduces repetitive behavior and symptoms that look like anxiety and being noncommunicative:

In a paper published two years ago in the journal Cell, Mazmanian and several colleagues fed B. fragilis from humans to mice with symptoms similar to autism. The treatment altered the makeup of the animals’ microbiome, and more importantly, improved their behavior: They became less anxious, communicated more with other mice, and showed less repetitive behavior.

Exactly how the microbes interact with the illness—whether as a trigger or as a shield—remains mostly a mystery. But Mazmanian and his colleagues have identified one possible link: a chemical called 4-ethylphenylsulphate, or 4EPS, which seems to be produced by gut bacteria. They’ve found that mice with symptoms of autism have blood levels of 4EPS more than 40 times higher than other mice. The link between 4EPS levels and the brain isn’t clear, but when the animals were injected with the compound, they developed autism-like symptoms.

Lactobacillus and bifidobacterium reduce anxiety-like symptoms in mice, while gut bacteria from anxious humans increases anxiety-like symptoms in mice:

Stephen Collins, a gastroenterology researcher at McMaster University in Hamilton, Ontario, has found that strains of two bacteria, lactobacillus and bifidobacterium, reduce anxiety-like behavior in mice (scientists don’t call it “anxiety” because you can’t ask a mouse how it’s feeling). Humans also carry strains of these bacteria in their guts.

Collins transferred gut bacteria from anxious humans into “germ-free” mice—animals that had been raised (very carefully) so their guts contained no bacteria at all. After the transplant, these animals also behaved more anxiously.

Humans who were fed the a favorite food of Lactobacillus and Bifidobacteria—galactooligosaccharide (GOS)—ended up with lower levels of cortisol and were drawn more to positive words:

Some subjects were fed 5.5 grams of a powdered carbohydrate known as galactooligosaccharide, or GOS, while others were given a placebo. Previous studies in mice by the same scientists had shown that this carb fostered growth of Lactobacillus and Bifidobacteria; the mice with more of these microbes also had increased levels of several neurotransmitters that affect anxiety, including one called brain-derived neurotrophic factor.

In this experiment, subjects who ingested GOS showed lower levels of a key stress hormone, cortisol, and in a test involving a series of words flashed quickly on a screen, the GOS group also focused more on positive information and less on negative.

Gut bacteria produce many chemicals that could potentially affect the brain:

It’s not yet clear how the microbiome alters the brain. Most researchers agree that microbes probably influence the brain via multiple mechanisms. Scientists have found that gut bacteria produce neurotransmitters such as serotonin, dopamine and GABA, all of which play a key role in mood (many antidepressants increase levels of these same compounds). Certain organisms also affect how people metabolize these compounds, effectively regulating the amount that circulates in the blood and brain. Gut bacteria may also generate other neuroactive chemicals, including one called butyrate, that have been linked to reduced anxiety and depression. Cryan and others have also shown that some microbes can activate the vagus nerve, the main line of communication between the gut and the brain. In addition, the microbiome is intertwined with the immune system, which itself influences mood and behavior.

Two types of effect not clearly stated in this extensive just above are the possibilities that (a) certain gut bacteria could intercept and neutralize chemicals from food that might otherwise affect the brain and (b) certain gut bacteria could intercept and neutralize chemicals that might otherwise damage the intestinal wall, which in turn would let other nasty chemicals into the bloodstream.

Why would certain types of gut bacteria do helpful things? One possibility is that it might help aid the spread of that type of gut bacteria:

Cryan suggests that over time, at least a few microbes have developed ways to shape their hosts’ behavior for their own ends. Modifying mood is a plausible microbial survival strategy, he argues that “happy people tend to be more social. And the more social we are, the more chances the microbes have to exchange and spread.”

The other possibility is that, other things equal, killing off one’s host is bad for the spread of one’s type of bacteria. But it takes many humans dying over a long period of time for this to create significant cumulative evolutionary pressure towards nice bacteria, and any change in dietary habits can put in motion a much quicker process of nasty bacteria flourishing.


There are many things about gut bacteria that we still don’t understand. For a simple example, to what extent do gut bacteria themselves burn calories so that get absorbed through the intestinal wall are less than the calories that are eaten?

In terms of guesswork, an argument I alluded to above is that it takes many generations of humans, with those infested with bad gut bacteria being more likely to die, in order to cumulate a significant evolutionary advantage to nice gut bacteria. That is, coevolution of gut bacteria with humans requires many human generations, since it is differential survival of the human hosts that gives an advantage to the nice bacteria. Other than evolutionary pressures from the deaths or degradation of human hosts, evolutionary pressures on bacteria are all for the benefit of the bacteria, not for the benefit of humans.

Evolutionary pressures on bacteria for the benefit of the bacteria, without regard to their effects on their human hosts, can act very fast. It is likely to be quite delicate to maintain a short-run equilibrium that keeps a nice type of bacteria ahead of the nasty type of bacteria for long enough to gain the long-run benefit from human hosts not dying as much. Dietary changes could easily disrupt that short-run equilibrium so things shift toward a nasty type of bacteria that persist for a long time before the long-run disadvantage of killing of human hosts takes its toll on that type of bacteria.

So the bottom line is that it is wise to eat in a way that is close to how our ancestors ate over the period of time when gut bacteria coevolved to be nice to humans. Eating in a newfangled way that changes the competitive environment for bacteria is likely to hurt the competitive strength of some of the old friends we have among gut bacteria. “True paleo” (as distinct from what is called “paleo”) is what I talk about in ““What Steven Gundry's Book 'The Plant Paradox' Adds to the Principles of a Low-Insulin-Index Diet.”

In principle, we should be able to figure out the details of which bacteria we need to take care of to stay healthy and what we need to do for them. In the meanwhile, before we have figured everything out about the gut microbiome, eating in a fairly traditional “true paleo” way is a good precautionary strategy.

Don’t miss my other posts on diet and health:

I. The Basics

II. Sugar as a Slow Poison

III. Anti-Cancer Eating

IV. Eating Tips

V. Calories In/Calories Out

VI. Wonkish

VIII. Debates about Particular Foods and about Exercise

IX. Gary Taubes

X. Twitter Discussions

XI. On My Interest in Diet and Health

See the last section of "Five Books That Have Changed My Life" and the podcast "Miles Kimball Explains to Tracy Alloway and Joe Weisenthal Why Losing Weight Is Like Defeating Inflation." If you want to know how I got interested in diet and health and fighting obesity and a little more about my own experience with weight gain and weight loss, see “Diana Kimball: Listening Creates Possibilities and my post "A Barycentric Autobiography.

John Locke: Legitimate Taxation and other Appropriation of Property by the Government is Limited as to Quantity, Procedure and Purpose

John Locke takes for granted the necessity of taxes, but stipulates three conditions for taxes and other government appropriations of property to be legitimate.

  1. The taxes cannot be so high that some individuals would be better off in the state of nature than as taxpayers within the nation.

  2. The taxes must be approved by some kind of majority vote of the populace representatives of the populace who still have the interests of the populace at heart.

  3. The taxes must be for the good of the nation as a whole—or at least include among their beneficiaries many who are not themselves politically powerful.

These views are laid out in John Locke’s 2d Treatise on Government: Of Civil Government, Chapter XI (“Of the Extent of the Legislative Power”), Sections 138-140.

The first point—that taxes cannot be so high that some individuals would be better off in the state of nature instead, I infer from the beginning of Section 138:

 §. 138. Thirdly, The supreme power cannot take from any man any part of his property without his own consent: for the preservation of property being the end of government, and that for which men enter into society, it necessarily supposes and requires, that the people should have property, without which they must be supposed to lose that, by entering into society, which was the end for which they entered into it: too gross an absurdity for any man to own. 

The remainder of Section 138 sets forth the need for representatives to approve taxes who still have the populace’s interests at heart:

Men therefore in society having property, they have such a right to the goods, which by the law of the community are theirs, that nobody hath a right to take their substance or any part of it from them, without their own consent: without this they have no property at all; for I have truly no property in that, which another can by right take from me, when he pleases, against my consent. Hence it is a mistake to think, that the supreme or legislative power of any commonwealth can do what it will, and dispose of the estates of the subject arbitrarily, or take any part of them at pleasure. This is not much to be feared in governments where the legislative consists, wholly or in part, in assemblies which are variable, whose members, upon the dissolution of the assembly, are subjects under the common laws of their country, equally with the rest. But in governments, where the legislative is in one lasting assembly always in being, or in one man, as in absolute monarchies, there is danger still, that they will think themselves to have a distinct interest from the rest of the community; and so will be apt to increase their own riches and power, by taking what they think fit from the people: for a man’s property is not at all secure, though there be good and equitable laws to set the bounds of it between him and his fellow subjects, if he who commands those subjects have power to take from any private man, what part he pleases of his property, and use and dispose of it as he thinks good. 

The beginning of Section 139 then speaks of “consent”:

§. 139. But government, into whatsoever hands it is put, being, as I have before shewed, intrusted with this condition, and for this end, that men might have and secure their properties; the prince, or senate, however it may have power to make laws, for the regulating of property between the subjects one amongst another, yet can never have a power to take to themselves the whole, or any part of the subjects’ property, without their own consent: for this would be in effect to leave them no property at all.

Consent is then defined in Section 140 as majority approval:

§. 140. It is true, governments cannot be supported without great charge, and it is fit every one who enjoys his share of the protection should pay out of his estate his proportion for the maintenance of it. But still it must be with his own consent, i. e. the consent of the majority, giving it either by themselves, or their representatives chosen by them: for if any one shall claim a power to lay and levy taxes on the people, by his own authority, and without such consent of the people, he thereby invades the fundamental law of property, and subverts the end of government: for what property have I in that, which another may by right take, when he pleases, to himself?

For current debates, John Locke’s most important stipulation is about the legitimate purposes of taxation. In the latter part of Section 139, he is not explicit about exactly what purposes are appropriate, but has a very revealing parable: a general can order a soldier to almost certain for a public purpose—the preservation of the nation from destruction by its enemies in war—but cannot legitimately steal a penny from the soldier for the general’s personal enrichment:

And to let us see, that even absolute power, where it is necessary, is not arbitrary by being absolute, but is still limited by that reason, and confined to those ends, which required it in some cases to be absolute, we need look no farther than the common practice of martial discipline: for the preservation of the army, and in it of the whole commonwealth, requires an absolute obedience to the command of every superior officer, and it is justly death to disobey or dispute the most dangerous or unreasonable of them; but yet we see, that neither the serjeant, that could command a soldier to march up to the mouth of a cannon, or stand in a breach, where he is almost sure to perish, can command that soldier to give him one penny of his money; nor the general, that can condemn him to death for deserting his post, or for not obeying the most desperate orders, can yet, with all his absolute power of life and death, dispose of one farthing of that soldier’s estate, or seize one jot of his goods; whom yet he can command any thing, and hang for the least disobedience; because such a blind obedience is necessary to that end, for which the commander has his power, viz. the preservation of the rest; but the disposing of his goods has nothing to do with it.

Debates about quantity and procedure for taxes are frequent and obvious in the news. Debates about purpose of taxes are even more frequent, but come in a slightly different guise: they show up as debates about whether particular government expenditures are appropriate or not. In many countries, the battle for what John Locke argues for in these three sections has been won. We are fortunate to have democratic governance of taxes and government spending.

Quartz #69—>The Most Effective Memory Methods are Difficult—and That's Why They Work

Here is the full text of my 69th Quartz column, "The most effective memory methods are difficult—and that's why they work," now brought home to supplysideliberal.com. It was first published on August 8, 2018. Links to all my other columns can be found here.

If you want to mirror the content of this post on another site, that is possible for a limited time if you read the legal notice at this link and include both a link to the original Quartz column and the following copyright notice:

© August 8, 2018: Miles Kimball, as first published on Quartz. Used by permission according to a temporary nonexclusive license expiring June 30, 2020. All rights reserved.

The column itself is between divider lines. Below the text of the column itself are some passages that were cut to keep the column tight, plus suggested reading.

In the 2014 book Make It Stick: The Science of Successful Learningauthors Peter Brown, Henry Roediger, and Mark McDaniel describe which learning techniques work, and which ones don’t. I can distill their message into one sentence:

If it isn’t making you feel stupid, it isn’t helping you learn.

Since most people like to feel smart, they run away in terror from learning techniques that make them feel dumb. Instead, they mistakenly focus on methods that give them the satisfaction of feeling like they’re improving in real time. Some of the most common ones are:

  • rereading a textbook

  • underlining and highlighting key themes

  • burning an idea into your memory by going over it again and again and again in a single intense session

  • waiting until you fully understand an idea to try to apply it or explain it

But unfortunately, any improvements made evaporate quickly with these methods.

What makes knowledge and understanding stick in the long run is studying in a way that guarantees that you fail and fail and fail. Testing your knowledge and understanding in ways that make you realize what you don’t know is the rocky path to genuine learning. The details are in a battalion of studies the authors cite—many in which they participated. These studies make the key points: testing your memory, mixing things up with different kinds of conceptsestablishing memory cues, and generally making things hard on yourself are crucial.

It’s a no pain, no gain philosophy. After all, real life is hard—it taxes your memory, mixes things up, and rarely gives you multiple choice options. Any approach to learning that isn’t hard won’t match what you experience in real life.

There are three key activities that effectively sear what you want to learn into your long-term memory:

  1. Doing things in real life, or in a simulation as close to the real thing as possible.

  2. Flashcards done right.

  3. Building your own picture and story of the ideas.

Let’s dig into each of these in turn.

“Practice like you play, and you’ll play like you practice.”

This is a key bit of folk wisdom endorsed by the authors of Make It Stick. The military conducts war games. Pilots train on simulators. Footballers practice scrimmages against second-string “scout teams” who mimic the strategies of their next opponents. If you only run the drills in optimal, predictable conditions, you’re never going to be prepared for a curveball. (Quite literally in the case of baseball—practicing hitting unpredictable pitches has been shown to do a lot more good than concentrating on hitting one type of pitch at a time.)

If you are a student, you need to do practice exams under conditions that are as close as possible to the real ones. If you aren’t allowed notes on the real exam, don’t allow yourself any notes when you do a practice exam. If you have to write an essay on the real exam, force yourself to really write an essay for the practice exam. Most importantly, do the practice exam under exactly the same time limits as the real exam. That way you can learn whether you get flustered by time limits and if there are things you get right but can’t do fast enough yet.

In non-academic settings, you can’t expect to learn much by just watching. For example, you can drive to the store 20 times while relaxing in the passenger seat and still not know the route yourself. But once or twice driving there yourself—making your own mistakes along the way and correcting them—and you’ll have the route nailed.

In the modern era, we’re often in the driver’s seat physically, turning the steering wheel, but rely so heavily on directions from our smartphones that we still don’t learn how to get from point A to point B. If you are sure a crutch will always be there for you, then using it counts as “practicing like you play.” But practicing with a crutch doesn’t prepare you well for a time when the crutch isn’t there.

The work counterpart to having someone else drive is letting the IT department just fix your computer problem rather than first trying fix it yourself. It is awfully hard to learn how to do something without doing it, however messy or unsuccessful your attempt.

Recall a piece of information repeatedly

Most of the information we absorb in a typical day is not only forgettable: It should be quickly forgotten. Do you really want to remember forever all the menu items you didn’t choose for lunch or what all the strangers you passed today on the sidewalk were wearing?

So how does your brain know whether something should be put into your long-term memory or not? Research finds that that attempting to remember an item repeatedly over an extended period of time is what puts it into long-term memory.

This means you need to intentionally try to retrieve items from your memory repeatedly to make them stick. The catch is that you can’t wait too long, nor try to solidify it too fast. If you try to remember too late after the fact, the original memory will be nowhere to be found; but if you wait only a few minutes to try to remember something, it’s too quick for you to signal your brain to put it into long-term memory. The key is to space out the attempts to remember in just the right way. The extensive references in Make It Stick include quite a bit of detail, but those results aren’t likely to be as useful as experimenting with the frequency and spacing that works best for yourself.

Done right, flashcards, whether they’re physical or virtual, are a great way to do memory retrieval practice. This is because they help space out attempts to remember an item, and you can come back to them easily periodically. But flashcards require some discipline in order to help. The number one principle is that you need to guess the answer before looking at the back of the card. Even if you think it is hopeless for you to remember, try. Sometimes you will surprise yourself. But even when you guess hilariously wrong, that effort of guessing carves out a space in your mind for the real answer to go—and you’ll definitely remember that’s not the right result next time.

The second principle is that you need to make it hard. Wait long enough between practice sessions—or put enough flashcards in the deck—that by the time a card comes around, you have to struggle to remember it. Third, cards you think you have down can be put in a slower rotation—but they shouldn’t go out of the rotation entirely. (Cards you make a mistake on can be put in a faster rotation.)

Another way to make memory-retrieval practice harder and really get your brain working is to shuffle in different kinds of tasks. The benefit of “interleaving” is one of the most surprising results from the research on learning, but it has been verified over and over again, such as in the batting practice study.

For example, if you are studying German vocabulary, have half the cards with German on top so you have to try to remember the English equivalent, and half the cards with English on top so you have to try to remember the German.  If you are using an app, choose one that switches between different types of challenges—like Duolingo, which tests you on verbal, aural, and text-based examples simultaneously—or go back and forth between apps on different subjects.

Teach what you are learning—if only to yourself

If you want to learn something you were taught or heard about, write about it in your own words, from memory, after the fact. It is great if you can find someone else to teach what you are learning to, but this principle works even if you just pretend to teach it.

If you had to explain things without notes, based only on your memory, what would you say? What are the most important ideas? How do they hook together? Why should your listener care about the ideas? Trying to figure out how to teach something not only involves a lot of retrieving things from memory—it also involves putting things together in a structure that creates a lot of memory cues. This creates hooks to hang the memories on and drag them out of hiding when you need them.

Another great way to teach yourself this structure-building skill is to try to guess where a teacher or manager is going next when they’re explaining a concept. Here you are harnessing the power of surprise and your competitive spirit to imprint things on your memory. If you made the right guess, you won; if not, it was a surprise. Either way, it will be more memorable.

The same technique will help you understand someone else’s point of view. In conversation, instead of trying to think of what you are going to say next or interrupting when you think you already know where things are going, say silently to yourself exactly what you think the other person will say next—then notice where you guessed wrong. Not only will you perhaps learn something you didn’t know—you’ll also be a better conversation partner.

Here are some passages that were cut, plus some further reading if you want to dig into this issue.

When people think of technological progress, they usually think of technological progress in the natural sciences and their applied wings: physics, biology, engineering and medicine, for example. Bu at least one area of the social sciences where technological progress has the potential to make a major difference to conventionally-measured GDP: the science of learning and teaching. Between learning and teaching, the science of learning comes first, since teaching is nothing more than helping someone to learn.

Some of the most exciting science about learning comes from psychologists rather than education school professors. ...

Implications for teaching. For teachers, this research on learning points to the value of anything that gets students to work hard during class. For example it helps to get students up to the board, to give them mini-quizzes or questions they answer with clickers, or to have students write a few sentences about what they learned at the end of class. But what really works for lasting learning is so individualized that classroom techniques only go so far.

In an extensive 2017 survey of randomized field experiments of schooling, Harvard economist Roland Fryer finds that tutoring is one of the few educational interventions with big effects. One likely reason for this is that tutors quite naturally challenge students in the way the ideal flashcard app would, as well as challenging students to explain concepts in their own words. The effectiveness of tutoring is not lost on college students. During the time I worked at the University of Michigan, so many students from relatively well-off families were hiring tutors as a boost to their coursework that many of our economics graduate students could make just as much money being a tutor as they could as official teaching assistants.

The trouble with human tutors is that they are expensive. Fortunately, there is hope that computers can become better and better tutors. Typical classes are so ineffectively taught that learning software designed to go along with the regular curriculum typically doesn’t do much good, but experimental evidence already indicates the value of learning software designed to act as a tutor.

But you don’t need a tutor or tutoring software to be an ace learner. All you need is the courage and determination to brave the hard knocks of techniques that constantly make you feel stupid by showing you what you don’t know yet.

Conclusion. There are some other things to learn about learning. For example, there are excellent tricks to get good memory cues: The alphabet song has helped millions of kids master the alphabet, the acronym OCEAN has helped psyche students remember the Big Five personality traits and memory champions use more elaborate “memory palace” techniques (described here) that also work like a charm. But the basic principle is the one above:

If it isn’t making you feel stupid, it isn’t helping you learn.

Or less bluntly, in the words of Peter Brown, Henry Roediger, and Mark McDaniel in Make It Stick:

Learning is deeper and more durable when it’s effortful. Learning that’s easy is like writing in sand, here today and gone tomorrow.

We are poor judges of when we are learning well and when we’re not. When the going is harder and slower and it doesn’t feel productive, we are drawn to strategies that feel more fruitful, unaware that the gains from these strategies are often temporary.

Related Columns:

Link to the Amazon page for Make It Stick

Suggested Further Reading by Make It Stick (quotation, bulleting added, bold changed to italics)

Scholarly Articles

  • Crouch, C. H., Fagen, A. P., Callan, J. P., & Mazur, E. (2004). Classroom demonstrations: Learning tools or entertainment? American Journal of Physics, 72, 835–838. An interesting use of generation to enhance learning from classroom demonstrations.

  • Dunlosky, J., Rawson, K. A., Marsh, E. J., Nathan, M. J., & Willingham, D. T. (2013). Improving students’ learning with effective learning techniques: Promising directions from cognitive and educational psychology. Psychological Science in the Public Interest 14, 4–58. Describes techniques that research has shown to work in improving educational practice in both laboratory and field (educational) settings, as well as other techniques that do not work. Provides a thorough discussion of the research literature supporting (or not) each technique.

  • McDaniel, M. A. (2012). Put the SPRINT in knowledge training: Training with SPacing, Retrieval, and INTerleaving. In A. F. Healy & L. E. Bourne Jr. (eds.), Training Cognition: Optimizing Efficiency, Durability, and Generalizability (pp. 267–286). New York: Psychology Press. This chapter points out that many training situations, from business to medicine to continuing education, tend to cram training into an intensive several day “course.” Evidence that spacing and interleaving would be more effective for promoting learning and retention is summarized and some ideas are provided for how to incorporate these techniques into training.

  • McDaniel, M. A., & Donnelly, C. M. (1996). Learning with analogy and elaborative interrogation. Journal of Educational Psychology 88, 508–519. These experiments illustrate the use of several elaborative techniques for learning technical material, including visual imagery and self-questioning techniques. This article is more technical than the others in this list.

  • Richland, L. E., Linn, M. C., & Bjork, R. A. (2007). Instruction. In F. Durso, R. Nickerson, S. Dumais, S. Lewandowsky, & T. Perfect (eds.), Handbook of Applied Cognition (2nd ed., pp. 553–583). Chichester: Wiley. Provides examples of how desirable difficulties, including generation, might be implemented in instructional settings.

  • Roediger, H. L., Smith, M. A., & Putnam, A. L. (2011). Ten benefits of testing and their applications to educational practice. In B. H. Ross (ed.), Psychology of Learning and Motivation. San Diego: Elsevier Academic Press. Provides a summary of the host of potential benefits of practicing retrieving as a learning technique.


  • Brooks, D. The Social Animal: The Hidden Sources Love, Character, and Achievement. New York: Random House, 2011.

  • Coyle, D. The Talent Code: Greatness Isn’t Born. It’s Grown. Here’s How. New York: Bantam Dell, 2009.

  • Doidge, N. The Brain the Changes Itself: Stories of Personal Triumph from the Frontiers of Brain Science. New York: Penguin Books, 2007.

  • Duhigg, C. The Power of Habit: Why We Do What We Do in Life and Business. New York: Random House, 2012.

  • Dunlosky, J., & Metcalfe, J. Metacognition. Los Angeles: Sage Publications, 2009.

  • Dunning, D. Self-Insight: Roadblocks and Detours on the Path to Knowing Thyself (Essays in Social Psychology). New York: Psychology Press, 2005.

  • Dweck, C. S. Mindset: The New Psychology of Success. New York: Ballantine Books, 2008.

  • Foer, J. Moonwalking with Einstein: The Art and Science of Remembering Everything. New York: Penguin, 2011.

  • Gilovich, T. How We Know What Isn’t So: The Fallibility of Human Reason in Everyday Life. New York: Free Press, 1991.

  • Gladwell, M. Blink: The Power of Thinking Without Thinking. New York: Little, Brown & Co., 2005. _______. Outliers: The Story of Success. New York: Little Brown & Co, 2008.

  • Healy, A. F. & Bourne, L. E., Jr. (Eds.). Training Cognition: Optimizing Efficiency, Durability, and Generalizability. New York: Psychology Press, 2012.

  • Kahneman, D. Thinking Fast and Slow. New York: Farrar, Straus and Giroux, 2011. Mayer, R. E. Applying the Science of Learning. Upper Saddle River, NJ: Pearson, 2010.

  • Nisbett, R. E. Intelligence and How to Get It. New York: W. W. Norton & Company, 2009.

  • Sternberg, R. J., & Grigorenko, E. L. Dynamic Testing: The Nature and Measurement of Learning Potential. Cambridge: University of Cambridge, 2002.

  • Tough, P. How Children Succeed: Grit, Curiosity, and the Hidden Power of Character. Boston: Houghton Mifflin Harcourt, 2012.

  • Willingham, D. T. When Can You Trust the Experts: How to Tell Good Science from Bad in Education. San Francisco: Jossey-Bass, 2012.

  • Worthen, J. B., & Hunt, R. R. Mnemonology: Mnemonics for the 21st Century (Essays in Cognitive Psychology). New York: Psychology Press, 2011.

'Is Milk Ok?' Revisited

Because I love dairy, I need to keep reanalyzing the evidence about possible downsides to milk and other dairy as I run across relevant articles. Anne Karpf’s article “Dairy Monsters” in the Guardian throws some additional curve balls about milk. Here I am going to limit myself to potential health worries about milk and dairy, leaving aside environmental concerns (which could be important). I will also leave aside lactose intolerance, because that issue is well understood.

Is It Just the Devil in Milk? First, there is a set of issues that could be entirely due to the A1 casein in regular milk, and possibly can be avoided simply by sticking to A2 milk—whether a2 brand cow’s milk or goat milk. See “Exorcising the Devil in the Milk.” Here are passages from the article above about this set of issues that could result from the structural weakness in A2 casein the lets a nasty 7-amino-acid peptide break off:

According to various studies, there's a whole catalogue of other illnesses that can be attributed to cows' milk, among them diabetes. A 1992 report in the New England Journal of Medicine corroborated a long-standing theory that proteins in cows' milk can damage the production of insulin in those with a genetic predisposition to diabetes. The dairy industry dismisses this as "just a theory" - along with "myth" and "controversial", a term it applies to almost all studies critical of milk.

The anti-milk lobby also claims that consumption of dairy products can aggravate rheumatoid arthritis and has been implicated in colic, acne, heart disease, asthma, lymphoma, ovarian cancer and multiple sclerosis.

Don’t Give Cow’s Milk to Infants! In addition, milk with A1 casein in it could be quite dangerous to give to infants, since infants drinking regular cow milk is is linked to Type 1 diabetes (more than where cow herds naturally lean toward the a2 casein). But there is another danger that should make you think thrice about giving infants cow milk:

Frank Oski, former paediatrics director at Johns Hopkins school of medicine, estimated in his book Don't Drink Your Milk! that half of all iron deficiency in US infants results from cows' milk-induced intestinal bleeding - a staggering amount, since more than 15% of American under-twos suffer from iron-deficiency anaemia. The infants, it seems, drink so much milk (which is very low in iron) that they have little appetite left for foods containing iron; at the same time, the milk, by inducing gastrointestinal bleeding, causes iron loss.

Animal Protein is a Problem. Second, there is the general problem that animal protein builds strong cancer cells. On this, see “Meat Is Amazingly Nutritious—But Is It Amazingly Nutritious for Cancer Cells, Too?” and the other posts flagged under “Anti-Cancer Eating” at the bottom of this post. Here is the relevant quotation from Anne Karpf’s article:

Major studies suggesting a link between milk and prostate cancer have been appearing since the 1970s, culminating in findings by the Harvard School of Public Health in 2000 that men who consumed two and a half servings of dairy products a day had a third greater risk of getting prostate cancer than those who ate less than half a serving a day.

In the same year, T Colin Campbell, the Jacob Gould Schurman Professor of Nutritional Biochemistry at Cornell University, said that "cows' milk protein may be the single most significant chemical carcinogen to which humans are exposed".

Not only is animal protein a problem in causing cancer, protein—especially animal protein—can contribute to osteoporosis. Here is Anne on that:

To the milk critics, the shibboleth that osteoporosis is caused by calcium deficiency is one of the great myths of our time (each side accuses the other of myth peddling). Mark Hegsted, a retired Harvard professor of nutrition, has said, "To assume that osteoporosis is due to calcium deficiency is like assuming that infection is due to penicillin deficiency." In fact, the bone loss and deteriorating bone tissue that take place in osteoporosis are due not to calcium deficiency but rather to its resorption: it's not that our bodies don't get enough calcium, rather that they excrete too much of what they already have. So we need to find out what it is that's breaking down calcium stores in the first place, to the extent that more than one in three British women now suffers from osteoporosis.

The most important culprit is almost certainly the overconsumption of protein. High-protein foods such as meat, eggs and dairy make excessive demands on the kidneys, which in turn leach calcium from the body. One solution, then, isn't to increase our calcium intake, but to reduce our consumption of protein, so our bones don't have to surrender so much calcium. Astonishingly, according to this newer, more critical view, dairy products almost certainly help to cause, rather than prevent, osteoporosis. …

A study funded by the US National Dairy Council, for example, gave a group of postmenopausal women three 8oz glasses of skimmed milk a day for two years, then compared their bones with those of a control group of women not given the milk. The dairy group consumed 1,400mg of calcium a day, yet lost bone at twice the rate of the control group. Similarly, the Harvard Nurses' Health Study found that women who consumed the most calcium from dairy foods broke more bones than those who rarely drank milk. Another piece of research found that women who get most of their protein from animal sources have three times the rate of bone loss and hip fractures of women who get most of their protein from vegetable sources, according to a 2001 National Institutes of Health study.

Thus, instead of drinking more milk, those worried about osteoporosis would be better advised to avoid animal protein. And exercise may also be a big help against osteoporosis, especially if started young:

A 15-year study published in the British Medical Journal found that exercise may be the best protection against hip fractures and that "reduced intake of dietary calcium does not seem to be a risk factor". Similarly, researchers at Penn State University concluded that bone density is affected by how much exercise girls get in their teen years, when up to half of their skeletal mass is developed. The girls who took part in this research had wildly different calcium intakes, but it had no lasting effect on their bone health.

Are There Countervailing Health Benefits of Milk? Some studies claim health benefits from milk. But:

The critics say these are small studies, in which other dietary and genetic factors, exercise and alcohol may swamp the effects of milk drinking. But couldn't the same accusation be levelled at studies revealing the malign consequences of milk? Not so, say the critics: those studies are far larger, build in the countervailing factors and still come up with a strong correlation between the saturated fats in milk and the risk factors for ill health.

And no claim that milk is essential to human health after weaning can stand up to even a cursory examination. The prevalence of lactose intolerance has led to broad scientific agreement that drinking milk after weaning is a relatively recent innovation for humans, and then only in some ancestries. A large fraction of people today, and in all likelihood an even larger fraction of ancestral humans have drunk very little milk after weaning, and have been fine.

Milk May Get in the Way of Vitamin D. Anne misses at least one important point. Despite talking about the importance of Vitamin D (see “Carola Binder—Why You Should Get More Vitamin D: The Recommended Daily Allowance for Vitamin D Was Underestimated Due to Statistical Illiteracy”) Anne misses T. Colin Campbell’s argument that dairy can inhibit the body’s production of the active form of Vitamin D. (I have a section on this in “Is Milk OK?”).

Balancing the Health Costs and the Culinary Benefits of Milk and Other Dairy. Despite all of this, I don’t intend to give up dairy. Health consequences have to be balanced against the pleasure one gets from a particular food. But how can I minimize any health costs from dairy? Here is my approach:

  1. Stick to A2 milk. On how, see “Exorcising the Devil in the Milk.”

  2. Keep your overall animal protein consumption down. If you love milk like I do, then you should eat less meat and eggs. I recently cut back my egg consumption from two per day to one per day to make more room for animal protein from milk.

  3. Substitute coconut milk for animal milk in anything it tastes almost as good.

  4. Take time off from food, frequently. That is, fast often for at least 16 hours, (a) to make it hard on your cancer cells, (b) to give your body a chance to make the active form of Vitamin D, (c) lower your insulin levels, and (d) to give your body a chance to repair itself in other ways.

  5. Consider milk and other dairy as a special treat and appreciate every bit of it. Try to keep the overall quantity down.

Conclusion. I believe there are many worse foods than milk. For people who don’t have obvious problems with milk, I advise them to worry first about eliminating sugar before worrying about dairy. However, switching to a2 milk is an obvious winner. Few of my readers are in a low enough income category that the extra expense of a2 milk (and goat or sheep cheese instead of cow cheese) will be a big deal, and the likely health benefits are large. Reading “Exorcising the Devil in the Milk” will put you onto an intervention with one of the best benefit/cost ratios in all of the diet and health area. (If you don’t believe me after reading that post, please post a comment on that post and I’ll think about what you have to say.)

Finally, let me emphasize that, in my view, milk fat is not a problem. The only thing I worry about with cream is the small amount of protein in the cream. I have my doubts about the first half of my earlier blog post title “Whole Milk Is Healthy; Skim Milk Less So but not the second half. Don’t ever drink skim milk and avoid all products made from skim milk! Lowfat products tend to have a high insulin index. (See “Forget Calorie Counting; It's the Insulin Index, Stupid.”) As a result, skim milk is less healthy—and in any case, if you are going to brave the possible health impact from milk, you might as well get the wonderful experience from full-fat milk!

Don’t miss my other posts on diet and health:

I. The Basics

II. Sugar as a Slow Poison

III. Anti-Cancer Eating

IV. Eating Tips

V. Calories In/Calories Out

VI. Wonkish

VIII. Debates about Particular Foods and about Exercise

IX. Gary Taubes

X. Twitter Discussions

XI. On My Interest in Diet and Health

See the last section of "Five Books That Have Changed My Life" and the podcast "Miles Kimball Explains to Tracy Alloway and Joe Weisenthal Why Losing Weight Is Like Defeating Inflation." If you want to know how I got interested in diet and health and fighting obesity and a little more about my own experience with weight gain and weight loss, see “Diana Kimball: Listening Creates Possibilities and my post "A Barycentric Autobiography.

The Religious Duty to Care about the Welfare of All Human Beings

As a Unitarian-Universalist, it is my duty to care about the welfare of every human being. The first of the “The 7 Principles of Unitarian Universalism” is “The inherent worth and dignity of every person”—and the second is like it: “Justice, equity and compassion in human relations.” There are no limitations of color, gender, ancestry, place of birth or citizenship to this these two principles.

Unitarian-Universalists are also expected to wrestle to figure out their own beliefs, both in relation to the supernatural and in relation to what is the highest good. When I had newly started attending the Unitarian-Universalist congregation in Ann Arbor, Michigan, back in 2000, I took a small class taught by the minister then, Ken Phifer (see his guest post “Kenneth W. Phifer: The Faith of a Humanist”). It was called “Building Your Own Theology.” Someday I’ll post the “Credo” (the “I believe”) that I developed in that class. But I have a somewhat more developed expression of my core religious beliefs in “Teleotheism and the Purpose of Life.” One way of putting that core belief is that a nascent God is working through us to bring God fully into being. Respecting the inherent worth and dignity of every person is a step toward bringing God fully into being.

Jesus said “I must be about my Father’s business.” My belief is that doing our best to make earth as close as possible to what we think heaven would be like is the business we must be about. Justice, equity and compassion in human relations is a key part of making earth more like heaven.

What follows, and the quotations below, comes from the Wall Street Journal article flagged above. Nine individuals associated with the Unitarian Universalist Church of Tucson have been charged with misdemeanor trespassing for trekking into the Sonoran desert to provide food—and more importantly, water—to people who otherwise might die of thirst there. They did not get the required permits to enter the Cabeza Prieta National Wildlife Refuge, because they intended to save lives in the desert in a way forbidden by law:

The defendants say they didn’t get permission to enter the refuge because of new rules adopted by the U.S. Fish and Wildlife Service forbidding Cabeza Prieta visitors from leaving behind food, water bottles, blankets, medical supplies or other personal possessions. 

Why would saving lives in this way be forbidden? Plausibly, in the pursuance of what I consider another injustice: laws that restrict legal immigration so much that people wanting a better life, in desperation, turn to illegal immigration.

Defense lawyers assert that the restriction on relief supplies—adopted by the Trump administration in July 2017—is part of a crackdown on border relief efforts. A defense motion quotes a text message from a Border Patrol agent referring to the volunteers as “bean droppers.”

This case raises interesting legal questions:

A central question in the case is whether the defendants are protected by the Religious Freedom Restoration Act, signed by President Clinton in 1993.

… Under the statute, the federal government may not hinder a person from exercising sincerely held religious beliefs without a compelling and unavoidable reason.

Department of Justice lawyers argue that the government has a compelling and unavoidable reason to inhibit this activity in order to use the possibility of dying of thirst in the Sonoran desert as part of the deterrence for illegal immigration, and that the provision of relief may result in the wilderness getting hurt or becoming less of a wilderness.

Prosecutors have also questioned whether the defendants’ relief missions are truly religious in nature, suggesting the defendants were motivated by political or “purely secular” philosophical concerns.

I suspect that, by implication, the prosecutors are questioning the religiousness of what I consider my religious beliefs as well. What would strike at the core of Unitarian-Universalism is a government rule that a a conviction can be religious only if it is based on the belief in something supernatural. Some Unitarian-Universalists believe in the supernatural, some don’t. They are all alike Unitarian-Universalists. Saying that

  1. those who believe in the supernatural have the protection of the religion clause of the First Amendment to the US Constitution and of the Religious Freedom Restoration Act, but

  2. those who, like me, believe that God can be brought forth within the natural world studied by physics,

would be unfair. Not as unfair as letting people die in the Sonoran desert, but unfair nevertheless.

My own activities on behalf of immigrants to the United States are all protected by the “freedom of speech” clause of the First Amendment, my religious beliefs are not legally pivotal for what I am doing. But I feel a lot of solidarity with those nine who felt that death of thirst was a cruel punishment for trying to become part of the miracle of nature and history that is the United States.

Don’t miss "The Hunger Games" Is Hardly Our Future--It's Already Here,” which pulls together many of my thoughts on immigration and provides links to other pieces I have written about immigration.

Oren Cass on the Value of Work

Beyond the day-to-day tussle in Washington and other capitals, one of the most important policy debates today is between advocates of a higher minimum wage, advocates of universal basic income and advocates of government wage matching. Oren Cass, in his interview by Jason Willick flagged above, makes a good case for wage matching. All the bullet points below (except the links to other posts at the very bottom) are quotations from this Wall Street Journal interview.

Work isn’t just about getting money. It is also about getting self-respect and respect from others:

  • Whether and how people are employed—what their role is in society’s productive system—“is both an economic and cultural question.”

  • Karl Marx speculated that workers with leisure time would “hunt in the morning, fish in the afternoon, rear cattle in the evening, criticise after dinner.” He was wrong. People out of the labor force—especially men—are more likely to be “sleeping and watching TV” than hunting or fishing, Mr. Cass says. Unemployment, more than any of life’s other rough patches, leads to unhappiness and family breakdown. People want to “know what our obligations are, and feel that we’re fulfilling them,” he adds. When this foundation of society starts to crumble, political upheaval tends to follow.

  • Work determines “whether we feel that we’re respected and admired,” Mr. Cass says, “and whether we have something that we’re good at.” Technocrats haven’t yet figured out how to redistribute self-esteem.

  • Can working-class Americans “buy more cheap stuff? Absolutely. And do we now transfer more money to them, so they can buy even more cheap stuff? Yes,” he says. “But their ability to participate meaningfully in the labor market, and to become self-sufficient supporters of families has eroded badly.”

Most of those at the bottom say they want jobs, not handouts:

  • … says Mr. Cass, the “further down the income ladder you go, generally speaking, the less enthusiasm there is for redistribution as a solution. People will tell you they want to work.” He adds: “It’s when you get to the top of the income distribution that you find a whole lot of people are basically like, ‘Why can’t I just write a check?’ ”

Oren advocates wages subsidies—a match rate by which the government matches a certain percentage of earnings. Funds would have to be found for wage matching in the government budget, but as a way to help those at the bottom who are able to work, wage matching has key advantages:

  • Unlike programs such as unemployment insurance, wage subsidies don’t reduce the incentive to work. His imagined subsidy would add a percentage of workers’ earnings to each paycheck up to a target amount, boosting the return on their labor.

  • Government benefits “can start to get pretty close to what a low-wage job provides in the market,” Mr. Cass says. In contrast, a wage subsidy increases the difference in value between social programs and work so that more people choose the latter.

One of Oren’s most intriguing points is that a wage-matching program needs to be paired with a cultural shift toward viewing low-skilled labor as honorable—and providing such jobs as honorable:

  • He argues that this widened economic gap between idleness and work should be paired with a cultural one, where idleness is stigmatized and work of all kinds is valued and celebrated. Today, he says, “being an employer of less-skilled workers is sort of a straight ticket to the exposé about how your workers don’t earn enough money.”

Personally, I find the line of attack that companies providing jobs for low-skilled workers are taking advantage of the government safety net especially annoying. Surely, offering jobs for low-skilled workers is better for society than not offering jobs for low-skilled workers. These workers need more take-home pay, but if we are OK with redistribution at all, it is appropriate that the take-home pay they need for a living wage should come from the taxpayers rather than hoping that an employer will react to a higher minimum wage by hiring more workers.

Wage matching can be even more powerful if paired with an online government-sponsored market for workers. Morgan Warstler designs such websites, and writes about their benefits in his Medium post “Guaranteed Income & Choose Your Boss: Uber for Welfare.” I have become more and more favorable to this idea over time. There are many benefits to government wage-matching done through a website like that for delivering Obamacare subsidies, but with more stability and a better user interface. Here is my list:

  1. There will be better incentives to work.

  2. There will be a lower cost for low-skill services—which will lower the cost of living, especially for those at the bottom, who can’t afford high-skill services. (Note that occupational licensing restrictions have to be relaxed to get the full benefit of this effect. One way to do this is by adding a new occupational category in each general area of work that is specifically designed for low-skill workers, and has few hoops to jump through. For example, it could be expected that someone meeting the definition for a “haircutter”—which might have only, say, one weekend’s worth of required training, entirely focused on safety—would have lower skill than someone meeting the definition for a “barber” or “hair stylist,” who has had to jump through more hoops.)

  3. With a star rating system (stars), those who have little experience, or are ex-cons, can develop a good record as workers.

  4. A star rating system for each day or at most each week of work makes the power one wields by a rating on any one occasion small enough that it should be hard to sue someone for giving a low rating for someone’s work. That contributes to honesty of those doing the rating. (There should also be ratings of bosses; that helps workers avoid choosing a bad employer.)

  5. Honest ratings of workers can lead to a lower natural (long-run-normal) rate of unemployment.

I explain the last point in my post “Janet Yellen is Hardly a Dove—She Knows the US Economy Needs Some Unemployment”:

Low pay affords workers an attitude of “Take this job and shove it!.” If workers have no reason to obey you because they are just as well off without the job—and owe you nothing—it will be hard to run a business. And if you hire someone at very low pay who actually sticks around, it is reasonable to worry about what is wrong with the worker that makes it so that worker can’t do better than the miserable job you are offering them. The way out of this trap is for an employer to pay enough that the worker is significantly better off with the job than without the job.

It might sound like a good thing that firms have a reason to pay workers more, except that, according to the Efficiency Wage Theory, firms have to keep raising wages until workers are too expensive for all of them to get hired. The reasoning goes like this: There will always be some jobs that are at the bottom of the heap. Suppose some of those bottom-of-the-heap jobs are also dead-end jobs, with no potential for promotion or any other type of advancement. If bottom-of-the-heap, dead-end jobs were free for the taking, no one would ever worry about losing one of those jobs. The Johnny Paycheck moment—when the worker says “Take this job and shove it”—will not be long in coming. If they were free for the taking, bottom-of-the-heap, dead-end jobs would also be subject to high turnover and low levels of emotional attachment to the firm. …

There are other conceivable ways to reduce the necessity of motivational unemployment in the long run.

  1. If all jobs had advancement possibilities—that is, no jobs were dead-end jobs—it might be possible to motivate workers by the hope of moving up the ladder. This works best if workers actually learn and get better at what they do over time by sticking with a job.

  2. If doing what needs to be done on the job could be made more pleasant, it would reduce the need for the carrot of above-market wages or the stick of unemployment.

  3. If workers could trust firms not to cheat them and were required to pay for their jobs, they would be afraid of having to pay for a job all over again if they were fired.

  4. There could be a threat other than unemployment, such as deportation.

  5. Unemployment could be made less attractive.

  6. Worker’s reputations could be tracked more systematically and made available online.

To make possibilities 5 and 6 more concrete, let me mention online activist Morgan Warstler’s … proposal that would make unemployment less attractive and would better track workers reputations: An “eBay job auction and minimum income program for the unemployed.” The program would require those receiving unemployment insurance or other assistance to work in a temp-job—within a certain radius from the worker’s home. The employer would go online to bid on an employee to hire and the wages would offset some of the cost of government assistance. Both the history of bids and an eBay-like rating system of the workers would give later employers a lot of useful information about the worker. Workers would also give feedback on firms, to help ferret out abuses.

(Even if it is reduced, if any motivational employment is necessary, it is an important thing to understand in macroeconomics. See “Why We Want More Jobs.”)

I suspect surveys show that a majority of Americans feel that those at the bottom should be able to make a living wage. Unfortunately, there is no guarantee that will happen without some government intervention. Consider the alternatives:

  1. Universal basic income makes people want to work less, making them more likely to forgo the non-money benefits of working as well as the money.

  2. Higher minimum wages make employers want to employ people less (especially when they are very high in relation to the marginal products of the relevant category of workers).

  3. Wage-matching honors work and, in particular, honors those who produce valuable output. And it helps the poor by giving them access to inexpensive services from their peers as well as by augmenting their wages.

Don’t miss these other posts (some of them link-posts to outside pieces) on these alternative policies:

On Food Preparation Memes

  Link to the Wikipedia article on “Nixtamalization”

Link to the Wikipedia article on “Nixtamalization”

An internet meme is only one type of meme. The current version of the Wikipedia article on memes explains them this way:

A meme acts as a unit for carrying cultural ideas, symbols, or practices, that can be transmitted from one mind to another through writing, speech, gestures, rituals, or other imitable phenomena with a mimicked theme. Supporters of the concept regard memes as cultural analogues to genes in that they self-replicate, mutate, and respond to selective pressures.

Food preparation memes matter when asking which types of food human beings are well adapted to. In “What Steven Gundry's Book 'The Plant Paradox' Adds to the Principles of a Low-Insulin-Index Diet” I discuss the idea of a true paleo diet that avoids grain and New World foods on the grounds that 10,000 years isn’t long enough for our genes to adapt well to grains or New World foods, and many of us have ancestries that have had much less time than that—the 500 some years since Columbus’s first transatlantic voyage—for our genes to adapt to New World food. One key issue is that the natural insecticides (of which many are classed as “lectins”) in edible plants can be hard on gut bacteria that aren’t adapted to them. And while bacteria can adapt very fast for their own benefit, for gut bacteria to coevolve with human beings so that they are beneficial for human beings requires a process in which human beings die or fail to fully thrive when things aren’t right. That process takes a long time.

A much faster type of adaptation is memetic adaptation—in this context, the evolution of food preparation memes. Some of the evolution of food preparation memes happens as a result of those who prepare foods badly dying or failing to thrive, and so having their descendants less represented in the population. But a lot of the evolution of food preparation memes can happen when people notice subtle signs that something they are eating isn’t treating them very well, and then tweaking the way they prepare their food until they feel good after they eat it with the new mode of preparation. Noticing how a particular type of food, prepared in a particular way, makes one feel is a lot easier when that food is one of a handful of staples, rather than just one of many types of food one is eating, as in the modern American diet.

Because of memetic evolution, traditional ways of preparing foods deserve a lot of respect. Conversely, even a food that has been around for a long time may need to be treated as if it is a new, untested food if a key step in the traditional mode of preparation is omitted.

Let me give a few examples of traditional methods of food preparation that may be important.

Rice with Vinegar or Pickled Vegetables: One seeming counterexample to the idea that easily-digested carbs make one fat by stimulating insulin is the many Japanese (and other East Asians) who eat rice at almost every meal and yet remain fairly lean. It is possible that because of a rice-eating ancestry that they have genes that help reduce the insulin spike from rice (I am not aware of any research on this), but another explanation is that they often combine rice with vinegar (to make sushi rice) or eat rice with pickled vegetables. Here is what Jason Fung says about vinegar in Chapter 16 (titled “Carbohydrates and Protective Fiber”) of The Obesity Code:

There are no long-term data on the use of vinegar for weight loss. However, smaller short-term human studies suggest that vinegar may help reduce insulin resistance. Two teaspoons of vinegar taken with a high-carbohydrate meal lowers blood sugar and insulin by as much as 34 percent, and taking it just before the meal was more effective than taking it five hours before meals. The addition of vinegar for sushi rice lowered the glycemic index of white rice by almost 40 percent. Addition of pickled vegetables and fermented soybeans (nattō) also significantly lowered the glycemic index of the rice. In a similar manner, rice with the substitution of pickled cucumber for fresh showed a decrease in its glycemic index by 35 percent.

Genuine Italian Tomato Sauce: In The Plant Paradox, Steven Gundry points to how after the Columbian exchange brought tomatoes to Europe, old-style Italian cooking traditionally peels, deseeds and cooks tomatoes before eating them.

Nixtamalization: In traditional New World cooking, maize (corn) was soaked and cooked in limewater or another alkaline solution, which was then drained before the maize was ground into meal for making corn tortillas. This did a lot to change the set of chemical compounds in the maize. I consider food made from corn suspect regardless, but I consider food made from corn especially suspect if the corn hasn’t been soaked in an alkaline solution along the way.

Soaking Oatmeal in an Acidic Solution: In The Plant Paradox, Steven Gundry recommends against eating wheat, barley, rye or oats. Giving up oatmeal has been a bit of a sacrifice for me, so I was heartened when I was able to find a blog post by Sarah Pope on a traditional way to prepare oatmeal: soak the oatmeal at least overnight in a ratio of 2 cups of oatmeal to 2 cups of water and 1/4 cup lemon juice or apple cider vinegar and a teaspoon of salt, then add 2 more cups of water in the morning and then cook for 5 minutes (I assume five minutes from when the water boils).

Sometimes, good food preparation memes come from modern science rather than from tradition.

Soaking Beans Overnight in Water: A comment by Rich on “What Steven Gundry's Book 'The Plant Paradox' Adds to the Principles of a Low-Insulin-Index Diet” pointed me to Michael Greger’s video “Dr. Gundry’s The Plant Paradox Is Wrong” on nutritionfacts.org, where Michael Greger’s big beef with Steven Gundry is that since beans have a lot of lectins, Steven Gundry’s worries about lectins seem anti-bean, while Michael Greger views nutrition research results as very pro-bean. Here is the first bit of my reply to the comment:

 I loved the videos on the nutritionfacts.org site!

The disagreement between Gregor and Gundry on beans is actually not that big. Gundry is very positive about pressure-cooked beans as a staple, recommending them especially to his many vegan patients. Gregor says that presoaking beans plus regular cooking also works to destroy the lectins.

Eating Carrots Raw: In “The Keto Food Pyramid” I advise:

It is only raw carrots that are OK. Cooked carrots have a higher glycemic index, suggesting a high insulin index.

I expand on this idea in “Why a Low-Insulin-Index Diet Isn't Exactly a 'Lowcarb' Diet”:

Raw vs. Cooked; Intact vs. Pulverized. One of the intriguing facts pointing to the importance of whether a type of cabohydrate is easily-digestible or not is one I discussed in "The Keto Food Pyramid": cooked carrots have a higher glycemic index than raw carrots. The glycemic index isn't the same thing as the insulin index, but within the same food group it is highly enough correlated with the insulin index that I use the glycemic index to guess the insulin index when direct data on the insulin index is not available. What this means is that you have to think not only about the processing of food by big food companies, but the processing of food that you do at home! In addition to what food you eat, you need to think about what you do to it before you eat it. Cooking carrots makes them easier to digest, so they cause a bigger spike in blood sugar. 

I don't know of anyone having done this experiment, but I'd love to see someone measure the insulin index of intact veggies as compared to veggies that have been run through a blender to make a veggie smoothie. I am betting that the veggie smoothie will have a higher insulin index than the very same ingredients if they are eaten intact. 

I should warn that many foods are not safe unless they are cooked. For example, it is widely recognized that beans can be poisonous if not cooked. And cooking can make things tastier. But in relation to causing insulin spikes, the category that matters is “easily-digestible carbs,” and cooking often makes things easily digestible.

Fruit vs. Fruit Juice: One of the big messages of “Forget Calorie Counting; It's the Insulin Index, Stupid” is that fruit juice has a much bigger insulin kick—which will soon make you hungry again—than whole fruit.

Conclusion: The bottom line is that how food is prepared matters. Because they are tested by time, traditional foods are typically more likely to be safe, but if they aren’t prepared in the traditional way, they aren’t traditional foods. Anything that isn’t a traditional food needs a lot of scientific analysis, with a skeptical eye. Traditional foods need to analyzed carefully, too, but it is modern processed foods that deserve the most skepticism from the get-go, as I argue in “The Problem with Processed Food.”

Don’t miss my other posts on diet and health:

I. The Basics

II. Sugar as a Slow Poison

III. Anti-Cancer Eating

IV. Eating Tips

V. Calories In/Calories Out

VI. Wonkish

VIII. Debates about Particular Foods and about Exercise

IX. Gary Taubes

X. Twitter Discussions

XI. On My Interest in Diet and Health

See the last section of "Five Books That Have Changed My Life" and the podcast "Miles Kimball Explains to Tracy Alloway and Joe Weisenthal Why Losing Weight Is Like Defeating Inflation." If you want to know how I got interested in diet and health and fighting obesity and a little more about my own experience with weight gain and weight loss, see “Diana Kimball: Listening Creates Possibilities and my post "A Barycentric Autobiography.

John Locke on the Importance of Established, Well-Publicized Laws

Martin Neimoeller famously said, of the Nazi government in Germany:

First they came for the socialists, and I did not speak out—because I was not a socialist. Then they came for the trade unionists, and I did not speak out— because I was not a trade unionist. Then they came for the Jews, and I did not speak out—because I was not a Jew. Then they came for me—and there was no one left to speak for me.

Blocking this strategy of coming for one group at a time, with the other groups thinking they are safe until it is too late is a key reason to adhere to John Locke’s principle of insisting the government operate according to established, known laws. He lays out this principle in his 2d Treatise on Government: Of Civil Government, Chapter XI (“Of the Extent of the Legislative Power”), Sections 136 and 137:

 §. 136. Secondly,[3] The legislative, or supreme authority, cannot assume to itself a power to rule by extemporary arbitrary decrees, but is bound to dispense justice, and decide the rights of the subject by promulgated standing laws, and known authorized judges: for the law of nature being unwritten, and so no where to be found but in the minds of men, they who through passion or interest shall miscite, or misapply it, cannot so easily be convinced of their mistake where there is no established judge: and so it serves not, as it ought, to determine the rights, and fence the properties of those that live under it, especially where every one is judge, interpreter, and executioner of it too, and that in his own case: and he that has right on his side, having ordinarily but his own single strength, hath not force enough to defend himself from injuries, or to punish delinquents. To avoid these inconveniences, which disorder men’s properties in the state of nature, men unite into societies, that they may have the united strength of the whole society to secure and defend their properties, and may have standing rules to bound it, by which every one may know what is his. To this end it is that men give up all their natural power to the society which they enter into, and the community put the legislative power into such hands as they think fit, with this trust, that they shall be governed by declared laws, or else their peace, quiet, and property will still be at the same uncertainty, as it was in the state of nature.

§. 137. Absolute arbitrary power, or governing without settled standing laws, can neither of them consist with the ends of society and government, which men would not quit the freedom of the state of nature for, and tie themselves up under, were it not to preserve their lives, liberties and fortunes, and by stated rules of right and property to secure their peace and quiet. It cannot be supposed that they should intend, had they a power so to do, to give any one, or more, an absolute arbitrary power over their persons and estates, and put a force into the magistrate’s hand to execute his unlimited will arbitrarily upon them. This were to put themselves into a worse condition than the state of nature, wherein they had a liberty to defend their right against the injuries of others, and were upon equal terms of force to maintain it, whether invaded by a single man, or many in combination. Whereas by supposing they have given up themselves to the absolute arbitrary power and will of a legislator, they have disarmed themselves, and armed him, to make a prey of them when he pleases; he being in a much worse condition, who is exposed to the arbitrary power of one man, who has the command of 100,000, than he that is exposed to the arbitrary power of 100,000 single men; nobody being secure, that his will, who has such a command, is better than that of other men, though his force be 100,000 times stronger. And therefore, whatever form the commonwealth is under, the ruling power ought to govern by declared and received laws, and not by extemporary dictates and undetermined resolutions: for then mankind will be in a far worse condition than in the state of nature, if they shall have armed one, or a few men with the joint power of a multitude, to force them to obey at pleasure the exorbitant and unlimited decrees of their sudden thoughts, or unrestrained, and till that moment unknown wills, without having any measures set down which may guide and justify their actions: for all the power the government has, being only for the good of the society, as it ought not to be arbitrary and at pleasure, so it ought to be exercised by established and promulgated laws; that both the people may know their duty, and be safe and secure within the limits of the law; and the rulers too kept within their bounds, and not be tempted, by the power they have in their hands, to employ it to such purposes, and by such measures, as they would not have known, and own not willingly.

An established, well-publicized law puts everyone on notice who might be affected by it, and so, if it is a bad law—and sometimes even if it is a good law—can arouse opposition before it is too late. Also, John Locke seems to be arguing that having to work by establishing in advance well-publicized laws will better energize the consciences of rulers—as well as the desire of even powerful rulers to look good, when we writes:

… the rulers too kept within their bounds, and not be tempted, by the power they have in their hands, to employ it to such purposes, and by such measures, as they would not have known, and own not willingly.

A final argument is that, whether a law is just or unjust, the cost of obeying the law will be lower if people can adjust to it:

 … the people may know their duty, and be safe and secure within the limits of the law …

This is a genuine effect, but John Locke does not discuss here the other effect of distortions that might arise from people gaming a law.

John Locke’s footnote within the passage above is closely related to my post “The Only Legitimate Power of Governments is to Articulate the Law of Nature”:

Note 3. Human laws are measures in respect of men whose actions they must direct, howbeit such measures they are as have also their higher rules to be measured by, which rules are two, the law of God, and the law of nature; so that laws human must be made according to the general laws of nature, and without contradiction to any positive law of scripture, otherwise they are ill made. Hooker’s Eccl. Pol. l. iii. sect. 9.
  To constrain men to any thing inconvenient doth seem unreasonable. Ibid. l. i. sect.10.

To me, that is an important message. Too often I here people talking as if a decision arrived at by proper procedure is ipso facto a legitimate decision. But what a government can legitimately do is circumscribed substantively as well as procedurally. Much of the US Constitution is about procedure, but the Bill of Rights is primarily about the substance of what the US government can legitimately do. The rule that laws be established and well-publicized is an important procedural guardrail. But it is not enough by itself.

Here I am drawn to think about administrative law: the administrative procedures law requires justification and a period of public comment for administrative rules. But there should also be substantive limits on what administrative agencies can do. And an important procedural rule for enforcing those substantive limits is the principle of judicial oversight by independently chosen judges. See “People Must Not Be Judges in Their Own Cases.”

For links to other John Locke posts, see these John Locke aggregator posts: 

Robert Plomin on the Progress of Social Science Genomics

Moore’s Law (a doubling of transistors per CPU every two years) has driven the astonishing rate of decline in computing. But in recent years, the cost of sequencing genes has been falling faster than the cost of computing. Currently, when done in bulk with quantity discounts, full sequencing costs about $100 per person, while “genotyping,” which captures all of the common variants, costs $25 or less per person.

I know this because I have recently added genomics to my research portfolio, starting with a research project focusing on the quantitative aspects of assortative mating. (Assortative mating is when people choose mates whose genes are more similar to them than would happen by chance.) Today I am on my way to a conference on "Polygenic Prediction and its Application in the Social Sciences" at the University of Southern California.

Robert Plomin’s Wall Street Journal teaser “Our Fortunetelling Genes” for his new book Blueprint: How DNA Makes Us Who We Are explains how polygenic scores have revolutionized social science genomics. First, Robert talks about the importance of the 1%:

About 99% of the 6 billion steps in the spiral staircase of DNA’s double helix are the same for all of us. This is what makes us human. Behavioral geneticists are interested in the 1% of DNA that makes us individuals. A century of research has found that these inherited DNA differences account for about 90% of the differences in people’s physical traits, such as height and eye color. What may come as a surprise is that DNA also accounts, on average, for about 50% of our differences in such psychological traits as personality, mental health and illness, and cognitive ability and disability.

The bad old days of genomics research were the era of the candidate gene studies. In the bulk of these studies, small samples met p-hacking to generate irreproducible results. The ethos of social science genomics is now laudably strict about standards of statistical significance, with adjustments for multiple hypothesis testing routine. (The social sciences outside of genomics should be much stricter. See “Let's Set Half a Percent as the Standard for Statistical Significance.”)

One of the best recipes for reproducibility is to get large samples. With large samples, even small effects can be detected. Robert writes:

… bigger is better when it comes to studies of heritability. … For bipolar disorder, going from 2000 cases in a 2007 study to 20,000 cases in 2017 increased the number of significant associations from zero to 30. The largest of these individual effects is minuscule, however; each one increases risk infinitesimally.

But what good are such tiny effects? The answer is that summing the effects of thousands of SNPs can create powerful DNA fortunetellers. These are called polygenic (“many gene”) scores, and they are the stuff of the coming DNA revolution in psychology.

With polygenic scores, we can predict psychological traits from inherited differences in DNA without knowing anything about the long and convoluted developmental pathways between genes and behavior, pathways that meander through gene expression, proteins and the brain. Unlike other predictors, this DNA fortuneteller can predict from birth because inherited DNA differences do not change from cradle to grave, from the single cell with which we begin life to the trillions of cells in our adult bodies.

My many-times-over coauthor Dan Benjamin is a leading light in the development of polygenic scores:

In 2013, in a paper in the journal Science, Daniel J. Benjamin of the University of Southern California and his colleagues in the Social Science Genetic Association Consortium used a sample of 125,000 individuals to produce a polygenic score that predicted 2% of the variance of educational attainment. In 2016, they used a sample of 294,000 and predicted 3% of the variance, as reported in the journal Nature Genetics. In 2018, with a sample of 1.1 million, the predictive power of their polygenic score jumped to more than 10% of the variance, as reported in Nature Genetics.

Years of education is a coarse but interesting variable because it captures what it takes to finish university, but the consortium also found that the polygenic score from their largest sample predicts up to 10% of the variance in general cognitive ability (that is, intelligence or IQ). My own research team, led by Andrea Allegrini, showed that this score also predicts 15% of the variance in nationwide tests of school performance in the compulsory subjects of English, mathematics and science given to all U.K. students at the age of 16, a finding that we previewed in the journal BioRxiv earlier this year.

The team Dan is on is busy putting polygenic scores into the datasets for major surveys such as the Health and Retirement Study that have genotyping data for the respondents. A lot can be done with these polygenic scores. Here is an example:

… Polygenic scores for educational attainment not only predict performance in school but also success later in life, such as mate choice, occupational status, social mobility and even financial planning for retirement, as shown by Daniel W. Belsky and colleagues at Duke University in a paper called “The Genetics of Success” that was published in the journal Psychological Science in 2016. The reason for the wider effects of the polygenic score for educational attainment is that it taps into other traits needed to succeed in higher education, not just intelligence but also qualities such as conscientiousness, grit and mental health.

Social science genomics seems to me to have enormous potential for doing good in the world. Those in the field of social science genomics don’t make the mistake of thinking that just because something is genetic that nothing can be done about it. Nothing could be further from the truth. The typical gene of interest to social scientists acts through a long change of causation, involving many steps within the social world—steps where the causality can readily be modified by policy.

A simple example can make clear how having a genetic cause can be consistent with effective interventions. There are genes for nearsightedness. But those genes only make people nearsighted in a truly damaging way if they can’t afford glasses or contact lenses. By the intervention of corrective lenses, we interrupt the effects those genes would otherwise have on eyesight from a functional point of view.

Another more speculative example also makes the point that showing that something has a genetic basis can sometimes mean it is easier, rather than harder to modify. Genetics may play an important role in whether or how much of the time someone has a leaky gut. But the consequences of a leaky gut are much more severe when you are eating things that are damaging once they get into the bloodstream. (See “What Steven Gundry's Book 'The Plant Paradox' Adds to the Principles of a Low-Insulin-Index Diet.”) Genes that predict those diseases because they predict a leaky gut might then also predict that dietary modifications could help.

Don’t miss this interview with Dan Benjamin and his coauthor Dalton Conley in the New York Times Magazine about this work

Also, don’t miss posts about work Dan Benjamin and I have been involved with and about his work with other coauthors: