On Teaching and Learning Macroeconomics

  Miles Kimball in Maui, November 2017—1/3 of a century wedding anniversary trip. Photo by Gail Kimball. See Gail's guest posts  here  and  here .

Miles Kimball in Maui, November 2017—1/3 of a century wedding anniversary trip. Photo by Gail Kimball. See Gail's guest posts here and here.

I have been thinking about macroeconomics for 42 years. As for many other areas, I have many strongly held views. Fortunately, by the customary standards of the economics profession, I have paid my dues enough that most economists would consider me to have earned the right to strongly held views, even if they disagree with them. 

In particular, I know personally the authors of many of the most popular macroeconomics textbooks, and am confident that they would be OK with me talking back to them on the question of how macroeconomics should best be taught. My dissertation advisor Greg Mankiw is the author of two bestselling macroeconomics textbooks: one at the Principles of Macro level and another at the Intermediate Macro level. Greg in particular would be OK with instructors having a back and forth dialectic between the views he presents and the views of the instructor of a macroeconomics course. 

Macroeconomics is a young field. Not everything in macroeconomics has been figured out. There are many things on which almost all macroeconomists agree. But there are many other things in macroeconomics on which there is no fully-agreed-upon consensus. So understanding macroeconomics requires learning to deal with debate. Dialectic, "the art of investigating or discussing the truth of opinions" (definition from Google), is an appropriate word here. Dealing with debate means not every issue will be nicely wrapped up in a bow. Students need to develop the skill to understand arguments, evaluate arguments, and formulate their own arguments. 

Although I have taught Principles of Macroeconomics and an advanced undergraduate Monetary and Financial Theory class many times in the past, currently, I teach the more advanced Intermediate Macroeconomics course required of economics majors. So I will focus most of my discussion here on Intermediate Macroeconomics. You can see a lot about how I approach my Intermediate Macro class on the fully public website for my Intermediate Macro class. (You might also be interested in the websites for my Principles of Macro class and for my Monetary and Financial Theory class.) 

There are two big purposes for taking a course in macroeconomics: gaining key skills, and gaining familiarity with key ideas related to macroeconomics. Let me start by laying out the key skill I want my students to gain, then touch on some of the ideas I want my students to become familiar with.

I consider the skills that students learn central because it is always possible to learn facts later on. But a college class is a golden opportunity to learn tough skills. Bryan Caplan has a book claiming that students don't really learn much in college. I hope that isn't true. And if it is true in general, I hope it isn't true in my class. 

  Link to the Amazon page for Bryan Caplan's book  The Case Against Education

Link to the Amazon page for Bryan Caplan's book The Case Against Education


Here are the skills I want my students to gain in my Intermediate Macro class:

  • Reading: the ability to read articles in the newspaper and posts in the blogosphere and understand them. 
  • Writing: the ability to think of an angle with some bite to it, come up with a thesis statement and defend it. 
  • Math: the ability to answer the question "how much" using the tool professional economists use routinely to answer this question: logarithms and the concept of a percent change as the change in a logarithm. 
  • Graphing and Logic: the ability to work through the implications of a shock on many variables in a complex set of graphs and to figure out the directions of some effects that might look ambiguous but aren't.]

Asking my students to write a blog post of their own each week, talking back to articles in the newspaper, articles online and even things I say, is the main way I organize things so students learn better how to write. I have had a lot of success in getting students to write quite well, as you can see from all the posts my students have written that I made into guest posts on this blog. I wrote "On Having a Thesis" and "Brio in Blog Posts" to help students with the basics of writing. I believe enough in the importance of writing that I spend significant class time early on talking about it. And the main job of my teaching assistant is to read and give feedback on students' writing. 

I hope that needing to get ideas to write about—and especially identifying other people's opinions they disagree with, helps students to learn to read better as well. In addition, I assign many of my own blog posts as extra reading assignments so that students are confronted with learning how to read and understand that kind of writing as well as to read and understand the kind of writing in the textbook. 

My starting point for teaching how to use logarithms and "Platonic" percent changes defined as the change in logarithms is to have them read "The Logarithmic Harmony of Percent Changes and Growth Rates." I push those techniques further in "The Shape of Production: Charles Cobb's and Paul Douglas's Boon to Economics" and in many exercises on my Intermediate Macro website. In particular, see the resources linked here.  

To teach graphing and logic, I emphasize a set of international finance graphs you can see below. I augment the large open economy graphs from Greg Mankiw's textbooks with an extra graph on the right showing physical investment as a function of the real interest rate. I also have two different versions: long-run and short-run. The long-run graphs have the market for loanable funds on the left, while the short-run graphs have the central-bank-determined real interest rate on the left. The other three graphs in the set of four stay the same between the long-run and short-run.   

If you want to see where logic comes in for resolving seeming ambiguities, take a look at this post from the class website. But it is quite advanced. Don't try until you are far along in my class or otherwise have a lot of training in economics. 

You can see my views about the primacy of skills in "The Coming Transformation of Education: Degrees Won’t Matter Anymore, Skills Will." I don't want my students to just get a degree. I want them to be able to impress employers with their skills, and to have the skills they need when they themselves becomes bosses. 


I don't get bent out of shape trying to expose my students to every significant idea in macroeconomics. That would be impossible in one semester, even given what they have already learned in Principles of Macro. My main hope for students to learn every significant idea in macroeconomics is for them to get interested enough in reading the news and reading in the economics blogosphere. Decades of reading beats whatever can be taught in one semester, hands down. 

In class, I have gravitated over time to a less-is-more approach, particularly in relation to the content of the textbook. I only use the first ten chapters of Greg Mankiw's Intermediate Macro textbook Macroeconomics. This gives me time to talk about other key concepts my students might have an especially hard time picking up elsewhere. From the textbook, the most important ideas are these:

  • The difference between the short run and long run. 
  • The art of economic modeling and how the concept of "exogenous" and "endogenous" set the boundary of any particular economic model; what is "exogenous"—outside the scope of things to be explained—in one econonomic model may be "endogenous"—within the scope of things to be explained—in another model. One objective of economic research is to bring more and more things within the scope of things to be explained by economic models. But in learning, it helps to start with simpler models and gradually work one's way up to models that bring more things within the scope of things to be explained. 
  • Why central banks are able to have a big, important effect on the economy in the short run, but in the long run can only affect inflation and other relatively important things like real money balances. 
  • Why net exports ("the trade balance") is determined by what people want to do with their savings. 
  • How the question of why some countries are rich and some countries are poor is basically the same question as why some countries have had a lot of economic growth and others haven't. (Hint: All countries used to be poor.) 
  • How the four main contributors to growth in per capita income are (a) physical capital accumulation, (b) education or "human capital accumulation," (c) copying technology from other countries, and (d) inventing new technology.
  • Why it takes a long time to see the benefits of physical or human capital accumulation. 
  • Where we are in relation to the potential of capital accumulation to raise long-run consumption. 

This is an impressive list. But many other important ideas are missing from most macroeconomic textbooks, even if one goes to the later chapters. Here are some of the ideas I consider so important that I teach them in class, and often have written blog posts to help explain them:

Finally, there are two ideas connected to the short-run/long-run distinction that are taught well in textbooks, but that I find I need to emphasize because it doesn't always get through:

  • In the short run, central banks control the nominal and therefore the real interest rate, but cannot control inflation. (I view not just the price level, but the rate of change in the price level as sticky or "sluggish" in Michael Kiley's terms. See "Trillions and Trillions: Getting Used to Balance Sheet Monetary Policy.")
  • In the long run, central banks control inflation and therefore the nominal interest rate, but cannot control the real interest rate. This means for example that pension funds that want a higher long-run interest rate are mistaken when they complain that central banks have made the long-run interest rate too low. 

One of the reasons I can get away with focusing on just ten chapters of Mankiw's Macroeconomics is my view that central banks are powerful enough to do the job of macroeconomic stabilization. That view is explained in "Even Central Bankers Need Lessons on the Transmission Mechanism for Negative Interest Rates," "Responding to Joseph Stiglitz on Negative Interest Rates" and "Negative Rates and the Fiscal Theory of the Price Level." Other than automatic stabilizers and the normal reaction of fiscal policy to monetary policy that I discuss in "Negative Rates and the Fiscal Theory of the Price Level," I view the proper role of fiscal policy as a long-run role. The two exceptions are:

  • In the months before the effects of monetary policy take hold—for that I recommend credit policy which is somewhere in between monetary policy and fiscal policy (see "Monetary vs. Fiscal Policy: Expansionary Monetary Policy Does Not Raise the Budget Deficit")
  • Some countries share their monetary policy with other countries. The euro zone is the most important example. Credit policy may be useful for macroeconomic stabilization when the shared monetary policy is not well-adapted to the regional situation. Denmark, which is not in the euro zone, but keeps a fixed exchange rate with the euro, has used credit policy to good effect. See my Wakelet story "Denmark's Brilliant Stabilization Policy." 

The other way that an appreciation of modern and next generation monetary policy can simplify teaching is the realization that interest rate targets make the details of the money multiplier relatively unimportant except in explaining the Great Depression and some of the investment mistakes people made during the Great Recession betting on inflation because they didn't understand that both the money multiplier and velocity had fallen dramatically. (On what I mean by next generation monetary policy, see "Next Generation Monetary Policy," "Alexander Trentin Interviews Miles Kimball on Next Generation Monetary Policy" and in relation to one dimension of next generation monetary policy, "The Economist: Improvements in Productivity Need to Be Accommodated by Monetary Policy.") 

Applying the Science of Successful Learning

Anyone who wants to be a B student, an A student or learn even more than that should read the book Make It Stick. I can summarize the main point this way. If you want to get knowledge into long-term memory, reading and rereading won't do the trick. Your brain only puts something into long-term memory if you prove to your brain that it is worth remembering that thing by trying to remember it. So the activity of trying to remember things is the key to learning something not just for the exam tomorrow but learning it for good.

Besides telling my students what I just said in the last paragraph, the way I use this principle in my class is by treating exams primarily as learning opportunities and only secondarily as evaluation devices. Exams cause students to try to remember things. Before each of the three exams, I ask students to do over the weekend the exam from the previous year as a practice exam—under time pressure. Then I go over that practice exam carefully in the class right before the exam. After the exam, I consider the class where I go over the answers one of the most important class periods for learning.

When I write each exam, I am thinking about what I most want students to remember down the road, since I know they will remember what ended up on the exams much more than any other specific things from the class. The answers to the exam questions represent the bulk of the key ideas and some of the key skills I want the students to take away from the class. 


"Macro" comes from the Greek word for "large." To me, macroeconomics is exciting because the issues it addressed are a big deal in the real world. Debates about macroeconomic policy are the heart and soul of macroeconomics. And anything that is a really big deal for overall economic welfare is appropriately a part of macroeconomics. It doesn't make sense to study macroeconomics without talking about the ways in which we might be able to make the world a better place by judicious economic policies that have a big effect on the economy as a whole.  

Finally, macroeconomics tends to focus on overall economic growth. But fairness is also important. In the buzzwords from Principles of Microeconomics, "equity" matters as well as "efficiency." The two topics I don't have time to cover in Intermediate Macro, but did cover when I taught Principles of Macro, were how to calculate present values to figure out how much saving you need to do for retirement, and how to apply diminishing marginal utility to think about social welfare functions. You can see a hint of how I taught those ideas on my Principles of Macro website. You can see more of how I approach social welfare functions in "What is a Supply-Side Liberal?" and "Inequality Aversion Utility Functions: Would $1000 Mean More to a Poorer Family than $4000 to One Twice as Rich?" To see why you should be concerned about issues of fairness, see Brad DeLong's eloquent technical discussion of the objective function of the free market here


Other Posts that Are on the Advanced Side, But Could Be Useful in Teaching Macroeconomics"



Using the Glycemic Index as a Supplement to the Insulin Index

Attaining and maintaining an appropriate weight is an increasingly rare accomplishment. It has, in expectation, many health benefits, as well as numerous other practical benefits. (See "The Heavy Non-Health Consequences of Heaviness.") If you share the goal of attaining and maintaining a healthy weight, it is important to focus on the timing of eating, as I argue in "Stop Counting Calories; It's the Clock that Counts." In addition, as I argue In "Forget Calorie Counting; It's the Insulin Index, Stupid," you should focus on the food insulin index in choosing which foods to eat. 

"Forget Calorie Counting; It's the Insulin Index, Stupid" gives an organized table of all the data on the food insulin index I have been able to lay my hands on so far. Unfortunately, there are many, many foods and beverages for which the insulin index has not been measured. Sometimes it is possible to guess the insulin index of a food or beverage from the insulin index for similar foods—especially when similar foods have a very high insulin index. But in other cases, not knowing the insulin index for a particular type of food makes it hard to guess whether that type of food is healthy or not. In some fraction of those cases, the glycemic index can be helpful, if used with great caution.

The big advantage of the glycemic index is that it has been measured for a huge range of foods and beverages. At the top of the post is a link to an especially extensive list that I use as my primary data source for this post. This list has several advantages. First, it shows the range of different estimates for different varieties of seemingly similar foods with very different glycemic indexes. Second, it gives standard errors. (Remember that you have to double the standard error on each side of the point index to get a 95% confidence interval.) Third, the article having been peer-reviewed makes me a little more confident that the numbers in the table are of reasonable quality. 

I focus here on what I learned from reading this table. Where the message is the same as in "Forget Calorie Counting; It's the Insulin Index, Stupid" (for example "Nuts are great!") I won't say much here. And indeed, the bulk of the table flagged above was saying that foods I categorized as unhealthy in "Forget Calorie Counting; It's the Insulin Index, Stupid" also look unhealthy through the lens of the glycemic index. 

Limitations of the Glycemic Index. 

The glycemic index measures the effect of a food or beverage on blood sugar. Since a surge in blood sugar reliably generates an insulin response, a high glycemic index almost always indicates a high insulin index. But the reverse is not necessarily true. A food or beverage can have a relatively low glycemic index while having a much higher insulin index. There are three big blind spots of the glycemic index:

  1. Protein often generates an insulin response. So meat and other high-protein foods are not as innocent as they appear from looking at the glycemic index.
  2. Oversimplifying a bit, fructose goes straight to the liver without staying long in the bloodstream. A large amounts of fructose going straight to the liver is not so great. So anything with fructose in it is much less innocent than it might appear from looking at the glycemic index.
  3. Though the science is at a much earlier stage than I would like, some types of nonsugar sweeteners boost insulin. So nonsugar sweeteners are not all as innocent as they appear from looking at the glycemic index. 

Although I focus here on what can be learned from the glycemic index, remember that you can experiment with yourself as a guinea pig and quickly learn a lot from your own experience. It doesn't take long for data you collect on yourself to have more statistical power than the typical data set in macroeconomics. And a close look at the table above shows that the precision in the table as indicated by the standard errors has often been achieved from studying a relatively small sample. So don't underestimate what you can learn from your own experience. 

The key to experimenting with yourself to guess how big an insulin kick a given food or beverage has is closely connected to why you should care about the insulin index in the first place. The big problem with high-insulin-index foods and beverages is that big spikes in insulin drive down blood sugar and make you hungry again relatively soon. And from my own experience and that of others I know well, I can say that consuming foods and beverages high on the insulin index can make it significantly more difficult to fast. (Though I don't fully understand the mechanism, subjective hunger during fasting, even 24 hours later, seems to be higher if one was eating foods high on the insulin index before beginning the fast.) So the way to get a read on the insulin kick of a given food or beverage is to pay attention to whether you feel hungry again relatively soon afterwards and whether you have extra difficulty fasting after consuming that food or beverage. My wife Gail and I use this approach all the time to get an additional reading on how healthy a given type of food is.  

Lessons from the Glycemic Index

In cases where protein, fructose and nonsugar sweeteners are not an issue, my rule of thumb for converting a glycemic index to an insulin index equivalent (as discussed in "Forget Calorie Counting; It's the Insulin Index, Stupid) is to multiply by 1.1. This rule of thumb uses the version of the glycemic index that gives glucose a glycemic index of 100, which is given in the leftmost column of numbers in the table flagged at the top of this post. Confusingly, sometimes a glycemic index with white bread as 100 is used. Making white bread instead of glucose 100 makes the number for the glycemic index 1.4 times as big. This explains some tables in existence that have glycemic indexes that look too high.

Combined with my rule of thumb of avoiding any food that has an insulin index of 50 or above, the rule of thumb of multiplying a glycemic index by 1.1 to get an insulin-index equivalent means my recommendation is to avoid anything with a glycemic index above 45. But I give a little extra leeway to whole fruit, since I find myself unable to completely shake the conventional wisdom that fruit is healthy. (I have no trouble in completely dismissing the conventional wisdom that fruit juice is healthy. It isn't. Fruit juice has way too much sugar that hits your system like a ton of bricks.) 

I should say that the advice of avoiding anything with an insulin index 50 or above or a glycemic index above 45 is for anyone who has ever had a problem with their weight. If you have been thin all your life so far, my advice is less rigorous: those who have always been thin might well be able to stay that way simply by strictly avoiding anything with added sugar or sugars, avoiding sweet beverages and processed food, and keeping their eating window each day down to 10 or 12 hours. I base this advice on my view of the epidemiology of obesity: the two things that have approximately the right timing to explain the secular rise of obesity are the ready availability of sugar, the rise of processed foods and beverages and the trend toward eating around the clock every waking moment. 

Now, to what I learned from studying glycemic index tables:

A. Bean and Lentils May Be OK.  The insulin index data on beans and lentils are quite sparse. The glycemic index data on beans and lentils are reassuring that they may be OK. But you should make sure to pay attention to data from your own experience as your own personal guinea pig for two reasons:

  • the glycemic indexes for different types of beans and lentils vary quite a bit;
  • it is possible that the protein in beans and lentils adds to their insulin kick. 

Nevertheless, I think it is quite reasonable to experiment and see if you can eat beans and lentils without getting too hungry later on. It should go without saying that you should avoid processed foods made from beans and lentils that have added sugar. Unfortunately, that will include most canned soup as well as many varieties of canned beans. On the likely dangers of sugar, see "Diseases of Civilization", "Sugar as a Slow Poison", "The Case Against Sugar: Stephan Guyenet vs. Gary Taubes", The Case Against the Case Against Sugar: Seth Yoder vs. Gary Taubes", and "Gary Taubes Makes His Case to Nick Gillespie: How Big Sugar and a Misguided Government Wrecked the American Diet." On processed food more generally, see "The Problem with Processed Food."

I should also warn that beans and lentils are likely to be in the category I labeled "Portion Sizes Should Be Kept Small Except on Special Occasions" in "Forget Calorie Counting; It's the Insulin Index, Stupid." In other words, beans and lentils are not freebies. My prediction is that most people can eat moderate amounts of them without getting rebound hunger, but will get rebound hunger if they eat large amounts of beans and lentils. 

B. Nonstarchy Vegetables are Indeed Good. In "Why a Low-Insulin-Index Diet Isn't Exactly a 'Lowcarb' Diet" I mirror Wikipedia's list of nonstarchy vegetables. Below I give that list again, plus a few additions, with glycemic index numbers beside them. Strangely, the table flagged above reports almost no glycemic indexes for nonstarchy vegetables, so these numbers are from other sources, particularly the charts I found by searching for Google Images related to the glycemic index. I mirror a few of those images after the list. When they disagreed, I chose the higher of the numbers. In the few cases when something had a high glycemic index I removed it from this list and put it on the list of (presumptively) starchy vegetables further below. 

  image source

image source

C. Starchy Vegetables are Bad, with the Exception of Carrots, Chickpeas and True Yams. The list flagged at the top was better at reporting glycemic indexes for starchy vegetables. I have spoken against potatoes before. There are so many entries for varieties of potatoes in the table flagged at the top I will let you do the "find" command within that pdf yourself to see them all. Here are some other starchy vegetables:

  • Beets (called "beetroot" in the table)  64
  • Carrots (raw)  16
  • Carrots (boiled)  41 (I averaged the 32 and 49 readings to get this number. The introduction to the table flagged at the top questions the 92 number, which comes from an early study that may not have been up to later standards.) 
  • Chickpeas (Garbanzo beans)  28
  • Corn  54
  • Fava beans (called "broad beans" in the table)  79
  • Hummus  6
  • Parsnips  97
  • Peas  48
  • Pumpkin  75
  • Rutabaga  72
  • Sweet potato  61
  • Yam  37


Carrots: The glycemic index of carrots depends a lot on whether they are raw or cooked.

Chickpeas: I am puzzled that hummus, which is ground-up chickpeas, would have a lower glycemic index than intact chickpeas. One possible reason is that different types of chickpeas have different glycemic indexes (the table flagged at the top has 10, 31, 33 and 36, averaged to 28) and hummus is often made from a type with an especially low glycemic index. But I don't know. 

Yams: In the United States and Canada, the word "yam" is often used to describe a sweet potato. But sweet potatoes are not true yams. Take a look at the Wikipedia article on yams.

D. Other Than Dates, Figs and Raisins, Dried Fruit May Be a Little Healthier than Fresh Fruit. This makes some sense to me: raisins, figs and dates are soft and so seem like they should be easily digestible. Most other dried fruit is tough and chewy, and may be digested more slowly than the corresponding fresh fruit. Here is the data I base this idea on—apples, apricots and plums vs. dates, figs and grapes—some from the table flagged at the top, some from the table mirrored just below the table. I am predicting that dried peaches will be more like dried apricots, apples and plums than like dried dates, figs or grapes. (Remember that dried fruit purchased in the store often has sugar added. That is a different matter. I am talking here about dried fruit with no sugar added. Also, remember that the quantity of dried fruit you are eating needs to be judged by the fresh fruit equivalent.)

  • Apple (raw)  38  (average of several types)
  • Apple (dried)  29
  • Apricots (raw)  57
  • Apricots (dried)  31
  • Plums  39
  • Prunes (dried plums) 15


  • Dates (dried)  103
  • Figs (raw)  35
  • Figs (dried)  67
  • Grapes  46
  • Raisins (dried grapes)  64
  image source

image source

For reference, here is the table of glycemic indexes and a few insulin indexes for fruit that I have in ""Forget Calorie Counting; It's the Insulin Index, Stupid":

Glycemic Index

  • tomatoes: 15
  • cherries: 20
  • grapefruit: 25
  • dried apricots: 32
  • pears: 38
  • apples: 39    (insulin index 43)
  • oranges: 40    (insulin index 44)
  • plums: 40
  • blueberries: 40
  • strawberries: 41
  • fresh peaches: 42    (insulin index 54 for peaches canned in juice)
  • bananas: 51   (insulin index 59)
  • grapes: 53   (insulin index 60)

E. Underripe Bananas May Be Healthier. I love bananas. But I don't eat them anymore because of their high insulin index. The glycemic index table flagged at the top suggests that underripe bananas have a lower glycemic index:

  • Banana overripe (Denmark) 52
  • Banana, overripe, yellow flecked with brown  (48)
  • Banana, ripe, all yellow (USA)  51
  • Banana, slightly underripe, yellow with green sections (USA)  42
  • Banana, underripe (Denmark)  30

I suspect a similar principle applies to other unripe fruit—for example the unripe mango that is an important ingredient in Southeast Asian cooking. 

F. Couscous and Popcorn Are Bad

  • Couscous  65
  • Popcorn  72

G. Pleasant Surprises

I don't trust the low glycemic indexes on a few types of cakes and cookies. Even if they were accurate for a particular type, it would be hard to know that what is still being made is the same type. But there are some pleasant surprises for less processed food that might be valid. Here are the pleasant surprises of relatively unprocessed food with a reasonably low glycemic index and no protein or fructose issue that I found in the table flagged at the top. I include some things where different types tested out differently, and it might be hard to find exactly the right type. I give a range of values. The experimental approach with oneself as guinea pig that I talked about above could be used to try to figure out if a given type was OK. 

  • Coarse Barley Bread  27, 34, 40
  • Pumpernickel bread  41, 41, 46, 55
  • Pearl barley  22, 22, 25, 27, 29
  • 27%+ amylose rice grown in Bangladesh  35, 32, 27, 33 
  • Mango  41, 51, 60, 51
  • Egg fettucine  32, 47, 40
  • Mung bean noodles  26, 39
  • Cheela (thin savory Bengali pancake made from legume flour batter)  42, 36, 45, 38
  • Dhokla (Gujarat cake-shaped dish made with a fermented batter derived from rice and split chickpeas)  35, 31, 33
  • Laddu (sphere-shaped sweets made of popped amaranth, foxtail millet, legume powder, fenugreek seeds, ghee and sugar or sweet sauce)  24, 29  (given the added sugar, this seems a bit too good to be true, but it might be worth the risk)
  • Nopal  7


A big reason I made the effort to study glycemic index tables was to identify a wider variety of food that you might be able to eat without getting an insulin backlash. As I emphasized above, you can quickly experiment to see if you do get hungry again soon after eating a particular food item, or if you have a hard time fasting after eating one of these types of food. So you will quickly be able to confirm or disconfirm the prediction implicitly made by the glycemic index measurements above. I hope the discussion above helps you find some additional types of food that are both tasty and work well with your weight loss or weight maintenance program. And I hope it helps you notice some types of food that mess up your weight loss or weight maintenance program so you can avoid those foods. Remember this rule of thumb: anything with a glycemic index of 27 or above could easily cause you trouble if you eat a lot of it. But a type of food with a glycemic index of 45 or so, might well be OK to eat in moderation. Try and see. 


Don't miss these other posts on diet and health and on fighting obesity:

Also see the last section of "Five Books That Have Changed My Life."


The Metaphor of a Nation as a Family

YouTube link to George Lakoff's lecture on Moral Politics

The metaphor of a nation as a family is a common and powerful metaphor. Indeed, George Lakoff argues in his excellent book Moral Politicsthat in the US, the central idea that holds Democratic Party views together is the idea that the government should be like a nurturing parent, while the central idea that holds Republican Party views together is the idea that the government should be like a strict father (a strict father who believes in a strong work ethic, among other things). Moral Politics is a book that will give you a lot more insight into politics.    

The metaphor of a nation as a family was also important in John Locke's day. In Sections 84-86 of his 2d Treatise on Government: “Of Civil Government,” in Chapter VII, "Of Political or Civil Society," John Locke argues against using the metaphor of a nation as a family as a justification for absolute power. To avoid distraction by John Locke's reprensively soft spot for slavery, I jump over a bit on slavery, giving that down at the bottom; otherwise, here is the passage:

  §. 84. The society betwixt parents and children, and the distinct rights and powers belonging respectively to them, I have treated of so largely in the foregoing chapter, that I shall not here need to say any thing of it. And I think it is plain, that it is far different from a politic society.

  §. 85. Master and servant are names as old as history, but given to those of far different condition; for a freeman makes himself a servant to another, by selling him, for a certain time, the service he undertakes to do, in exchange for wages he is to receive: and though this commonly puts him into the family of his master, and under the ordinary discipline thereof; yet it gives the master but a temporary power over him, and no greater than what is contained in the contract between them. But there is another sort of servants, which by a peculiar name we call slaves, ...  

§. 86. Let us therefore consider a master of a family with all these subordinate relations of wife, children, servants, and slaves, united under the domestic rule of a family; which, what resemblance soever it may have in its order, offices, and number too, with a little commonwealth, yet is very far from it, both in its constitution, power and end: or if it must be thought a monarchy, and the paterfamilias the absolute monarch in it, absolute monarchy will have but a very shattered and short power, when it is plain, by what has been said before, that the master of the family has a very distinct and differently limited power, both as to time and extent, over those several persons that are in it; for excepting the slave (and the family is as much a family, and his power as paterfamilias as great, whether there be any slaves in his family or no) he has no legislative power of life and death over any of them, and none too but what a mistress of a family may have as well as he. And he certainly can have no absolute power over the whole family, who has but a very limited one over every individual in it. But how a family, or any other society of men, differ from that which is properly political society, we shall best see, by considering wherein political society itself consists.

John Locke, knowing he can't completely fight the metaphor of a nation as a family is at pains to give something as close to a contract theory of the family as possible. Discussing employees along with spouses and children helps. John Locke uses the sexism of his time to further his argument in the passage "he has no ... [power] but what a mistress of a family may have as well as he," as in the passage I discussed in "Thinking of Mothers and Fathers On a Par Undercuts a Misleading Autocratic Metaphor." And he previously asserted the ultimate freedom of wives and children as I discussed in "Equality Before Natural Law in the Face of Manifest Differences in Station," "John Locke's Smackdown of Robert Filmer: Being a Father Doesn't Make Any Man a King," and "By Natural Law, Husbands Have No Power Over Their Wives."

The power of the metaphor of a nation as a family may help explain why in my now fairly extensive social media experience, the most heated attacks I get—other than for being positive about an individual someone despises—are when arguing that more needs to be done to attain true equality for women. Perhaps unconsciously, people sense that if women are seen as legitimate equals of men within families and other organizations, then it changes our image of the nation as well.   

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

The omitted excerpts on slavery from the passage above reads as follows: 

... slaves, who, being captives taken in a just war, are by the right of nature subjected to the absolute dominion and arbitrary power of their masters. These men having, as I say, forfeited their lives, and with it their liberties, and lost their estates; and being in the state of slavery, not capable of any property, cannot in that state be considered as any part of civil society; the chief end whereof is the preservation of property. ...


I can't be at the conference advertised above this year, but it is the Well-Being Measurement Initiative team I am on (and that accounts for by far the bulk of my research effort) that is organizing the conference whose program you see above. Let me talk a little about the field of study for our paper that my coauthors Dan Benjamin, Kristen Cooper and Ori Heffetz are presenting at the conference. 

"Tropozoic" and "Tropozoics." To maximize your utility, you need to make good decisions about your interactions with the market and good decisions about interactions with others in your household. But there are also many other important decisions you face in running your life. I want to propose and road-test a word for the study of the full range of decisions people face in running their lives, including private individual decisions that don't involve anyone else, except quite indirectly. 

In searching for a word for the study of the full range of decisions people face in running their lives, I looked for an analog to the word "household" in Gary Becker's phrase "household production function." Notice that in the phrase "household production function," the word "household" functions as if it were an adjective. I looked first and foremost for an adjective. 

For the concept of "having to do with the management of an individual life in all its dimensions, including things of the heart, mind and spirit as well as outward things," I propose the adjective "way-of-life" or its Greek-derivative equivalent "tropozoic." Thus, for example, I might say something like:

Understanding the nature of tropozoic production functions is important for helping people to have rich and abundant lives. 

Let me justify my choice of a Greek equivalent for "way-of-life." First, I think that for a technical term, using a Greek derivative is an easy way to avoid making people think of secondary meanings of an English word or phrase that are not relevant. Put "way of life" into Google Translate; you will get back the Greek τρόπος ζωής, which can be transliterated as trópos zoís. Tropos means "a turn, direction, course, way, and shows up in words such as "phototropic," which means "turning toward the light." Zoís is one of the Greek words for "life," and is behind the name Zoe. Tropozoic is the obvious form for an English adjective based on trópos zoís. As far as I know, in English, "tropozoic" is a new coinage.

With the adjective tropozoic in hand, it is easy to find a name for the study of tropozoic optimization and suboptimal tropozoic decision-making. Let me call it tropozoics, a noun for a field of social science at the point where economics, psychology, sociology and anthropology meet. 

Let me know what you think. 


Note: The philology of the three Greek roots for "life": bios, psuche and zoe and their derivatives in other languages is complex. Christian theology sometimes distinguishes zoe as a higher kind of life. (To be clear, as a nonsupernaturalist, I view religious practice as much more central to tropozoics than theoretical theology. Live: Teleotheism and the Purpose of Life, which has links to other key religion posts, is a good place to start if you are interested in my views on religion.) I think what is going on here is this: because zoe puts the focus on being alive as opposed to dead, metaphorically it can be used to express the idea of having a desirable life. This is akin to the way English phrase "I feel alive" points to a desirable life, while the English phrase "I feel dead inside" points to an undesirable life. This connotation of a desirable life in zoe or zoís is appropriate for the study of optimization and failures to optimize in relation to one's way of life. 

Bios can refer to "human lifestyles and activities" but it is not obvious how to make an attractive English adjective out of tropos bios. Bios has an English derivative "biography" in which it has exactly the right meaning, but in "biology" it has the same focus on the physical that zois has in "zoology."


On failures to optimize, don't miss "Cognitive Economics."


The Problem with Processed Food

In the Wall Street Journal teaser to her new book,  "Best Before: The Evolution and Future of Processed Food," Nicola Temple argues (in line with the title the editors gave to her piece) that we should "Give Processed Food a Break." 

Nicola gives these examples of relatively innocent food processing. (I numbered the excerpts.):

1. Our earliest ancestors pounded otherwise inedible tubers with rocks and sliced meat with primitive tools—processing methods that are credited with beginning the trend in our evolution toward smaller teeth and jaws and bigger brains. We spend only 5% of our day chewing our food, while our closest primate relatives, chimpanzees, spend 37% of their day that way, according to a 2011 study.

2. The prevalence of diseases related to nutrient deficiency has led to the mandatory fortification of processed foods such as salt and wheat.

3. Now the quest for more sustainable sources of protein and more awareness of animal welfare are driving the effort to develop “clean meat”—lab-cultured protein that doesn’t require the slaughter of animals.

4. ... there’s a nutritional case for frozen food generally over fresh. Vegetables and fruit destined for flash freezing are picked when they’re ripe, while fresh produce is usually picked underripe and artificially ripened closer to the point of sale. Produce starts to degrade the moment it is picked, and the “fresh” peas or tomatoes that have been traveling for a week are often less good for you than their frozen versions.

Finally, one of my daily staples—prewashed lettuce and spinach—depends on some processing. I don't know if I would have the meal-preparation stamina to eat as much lettuce and spinach as I do without this processing:

5. So what explains those lovely packaged, fresh-cut leaves in the supermarket? To limit microbial growth, companies must wash them one or more times with a disinfectant such as a chlorine solution or ozone added to water to label them as pre-washed, according to FDA guidelines. (Even those labeled “unwashed” are washed in water at least once.)

Nicola is certainly right that "food processing" can be either good or bad. But there are three reasons to be suspicious of food processing.

Most Food Processing Makes Food Easier to Eat and Enhances Digestibility. If carbohydrates are too easy to digest, they can cause a blood sugar and insulin spike up, followed by a blood sugar crash which tends to make people hungry again. Things as simple as cooking and juicing can work in this direction:

More generally, if food becomes easier to eat physically, and instantly ready, you are more likely to eat it when it is otherwise a bad idea to eat it. 

The Newer the Type of Food Processing, the Less Tested It Is By Time. There are some silly ideas in the Paleo diet—for example, treating honey as a freebie, when it is unlikely that our distant ancestors got their hands on honey all that often. But I agree with the basic idea that what our ancestors ate has been tested by time in a way newer versions of food haven't been. Human beings are fundamentally omnivores, so a large variety of foods have been well-tested by many, many thousand years worth of consumption experience.

Milk may have only a few thousand years worth of experience of testing behind it and so may be more problematic. (See "Is Milk OK?") And cancer hits preferentially at older ages that people often didn't make it to in any case in the bad old days; so potential problems such as the possibility that meat might contribute to cancer have not have been tested as well by time as one would like. (See "Meat Is Amazingly Nutritious—But Is It Amazingly Nutritious for Cancer Cells, Too?", "How Fasting Can Starve Cancer Cells, While Leaving Normal Cells Unharmed", Why You Should Worry about Cancer Promotion by Diet as Much as You Worry about Cancer Initiation by Carcinogens, and "Good News! Cancer Cells are Metabolically Handicapped.") On a different front, having regular meals has not stood the test of millenia. And there is reason to think the common custom of three meals a day is not that good for us. (See "Stop Counting Calories; It's the Clock that Counts.")

But any likely danger of milk, meat or regular meals pales in comparison with the dangers from newfangled types of food processing that have only affected ordinary people's diets in the last few hundred years. Sugar refining and flour milling are good examples. (See "Diseases of Civilization", "Sugar as a Slow Poison", "The Case Against Sugar: Stephan Guyenet vs. Gary Taubes", The Case Against the Case Against Sugar: Seth Yoder vs. Gary Taubes", and "Gary Taubes Makes His Case to Nick Gillespie: How Big Sugar and a Misguided Government Wrecked the American Diet.")

Types of food processing that came into their own in the 20th century or more recently should also be suspect. Some we know reasonably well to be bad, such as the hydrogenation of oil that put transfats into margarine. But it is the 20th-century and more recent food-processing practices we don't know yet are bad that I am even more worried about. It often takes decades for research to establish that something is bad. And it often takes decades for people to get interested enough in the question of whether something is bad to begin that arduous process of research. For many, many types of food processing, the right view is that we simply don't know if it is safe or not. A particular thing might be fine or it might be terrible. A few decades of experience isn't enough for us to know. I am willing to take my chances with modest amounts of some processed foods that serve important purposes for me personally; basic Ranch dressing and Halo Top ice cream come to mind. But I don't pretend to myself that I know they are altogether safe.  

Food Companies Have a Different Objective Function Than You Do—Or at Least a Different Objective Function Than Your Long-Run Self Does. I have saved my biggest concern about food processing for last. With a little bit of exaggeration, I can say that food companies are maximizing against you. What is their objective? They want you to buy a lot of their food. That may involve being able to claim their food is healthy, but typically doesn't involve in any big way actually having the food be healthy. In addition to being able to make claims that their food is healthy, they want to make it tasty, quick and addictive. (To avoid argument, let me define "weakly addictive" as "even when you already have a lot of experience with the food, if you eat one, it will make you want to eat more, as when Lay's bragged about the weakly addictive quality of its potato chips, advertising "bet you can't eat just one.") Food companies also care about your willingness to pay a premium price and keeping the cost per unit down, but getting you to buy a lot of their food is pretty important to their success. 

The basic message here is the one George Akerlof and Robert Schiller lay out in Phishing for Phools:

Food companies are not your friend. They are in it for themselves. The more complex the food processing they have done, the more room there is to trick you in some way. 

Here let me make an analogy to consumer finance companies. When a financial product is very complex, with lots of fine print, it opens up more ways to trick you. There, the government can help, as I argue in "On the Consumer Financial Protection Bureau." Unfortunately, at this point, the government is much more ignorant about what is safe and unsafe in our diets than it is about what is safe or unsafe in consumer finance. So it is best to stay away from complex processed products as much as possible (or as much as personally tolerable). At a minimum, you should consciously think about how much you trust a particular food company before you eat complex processed food they have created. 

Conclusion. Particular types of food processing may be innocent, but in my view, any particular type of food processing should be considered guilty until proven innocent. Some types of food processing have passed such a trial. Many, many haven't. 

Don't miss these other posts on diet and health and on fighting obesity:

Also see the last section of "Five Books That Have Changed My Life."


Ricardo Hausman: Tacit Knowledge Is a Key Component of Productivity; That Means Prosperity Depends on Allowing Skilled Immigration--Especially into Poor Countries

My graduate school contemporary Lant Pritchett interviews Ricardo Hausman. In a 5-minute video, Ricardo talks about how "technology" as measured by total factor productivity (or purified TFP) is really a combination of: 

  1. knowledge embodied in machines
  2. knowledge embodied in books or digital files
  3. knowledge embodied in human brains only in a nonconscious, tacit way

That means that to improve "technology," one should allow into one's country not only advanced machines, books and digital information, but also skilled individuals who have have important tacit knowledge. Remarkably, many poor countries are very restrictive in allowing skilled immigration. Ricardo argues that this not only hurts economic growth, it exacerbates inequality. 

I have a closely related blog post that you might also be interested in:

I should also mention that the YouTube page the video above is on has a wealth of other intriguing videos. 

Good News! Cancer Cells are Metabolically Handicapped

Being free of normal restraints can make a killer or a thief seem powerful. But it doesn't mean the killer is an evil genius like those so common in movies and on TV. My Dad, a criminal law professor, often told me stories about how stupid criminals are; he even cowrote a book about it in honor of one of his colleagues: Criminals are Stupid: A Tribute to Woody Deem

Being free of normal restraints can make cancer cells seem powerful. But the damage they have suffered that makes them go rogue is likely to handicap them in some way. There are mechanisms that keep cells on the straight and narrow. It would be hard for something to damage those good-behavior mechanisms without damaging something else as well.  

Thomas Seyfried, in his book Cancer as a Metabolic Disease: On the Origin, Management, and Prevention of Cancer argues persuasively that metabolic damage is a common path for a cell to break free of normal restraints. In Chapter 15, he writes:

According to my view, cancer cells proliferate and survive not because of their genomic instability, but because of their respiratory insufficiency. Respiratory insufficiency enhances fermentation, destabilizes the genome, and causes entry into the default state of unbridled proliferation [15]. ...

Fermentation energy is primal energy. Fermentation is linked to unbridled proliferation [15, 20]. ...

Unbridled proliferation is the default state of metazoan cells when released from active negative control [33–35].

Active respiration maintains the differentiated state and genome integrity through the RTG signaling system (Chapter 10).

To understand this passage, it is important to know how Thomas Seyfried is using the technical terms "respiration" and "fermentation." The current version of the Wikipedia article "Cellular respiration" explains:

Most of the ATP produced by aerobic cellular respiration is made by oxidative phosphorylation. This works by the energy released in the consumption of pyruvate being used to create a chemiosmotic potential by pumping protons across a membrane.

Thomas Seyfried uses the term "respiration" to refer to oxidative phosphorylation, or OxPhos. OXPHOS depends on pumping protons across the inner mitochondrial membrane, which is a delicate structure that must be constructed carefully and can easily be damaged. 

Fermentation is a similar chemical process in yeast, bacteria, and eukaryotes.  (All animals are "eukaryotes," including us). The current version of the Wikipedia article "Fermentation" describes it as follows: 

Fermentation is a metabolic process that consumes sugar in the absence of oxygen. ...

Along with photosynthesis and aerobic respiration, fermentation is a way of extracting energy from molecules, but it is the only one common to all bacteria and eukaryotes. It is therefore considered the oldest metabolic pathway, suitable for an environment that did not yet have oxygen.

Fermentation normally occurs in an anaerobic environment. In the presence of O2, NADH and pyruvate are used to generate ATP in respiration. This is called oxidative phosphorylation, and it generates much more ATP than glycolysis alone. For that reason, fermentation is rarely utilized when oxygen is available.

If Thomas Seyfried is right that cancer cells often have a damaged capability for OxPhos, then cancer cells can't extract as much energy from a given amount of nutrients as normal cells can. If there is plenty of sugar available, cancer cells will be able to do fine by taking in sugar and fermenting it. If there is less sugar available within the body, then it puts cancer cells at more of a disadvantage, since cells that can do OxPhos can wring more energy from each sugar molecule than is possible for a cell that can't do OxPhos and can only manage fermentation.

Thomas Seyfried is far from alone in thinking that many cancer cells are metabolically handicapped. A lot of research, including randomized clinical trials, are being conducted on the basis of this hypothesis, as I discuss in "How Fasting Can Starve Cancer Cells, While Leaving Normal Cells Unharmed." 

A key part of Thomas Seyfried's argument is that metabolizing glutamine and possibly other amino acids without OxPhos can mimic some of the indicators that many investigators use to judge whether OxPhos is intact or not. The following passage from Chapter 4 is important, but heavy going. The two main claims are

  • Metabolizing glutamine without OxPhos can create the illusion for a lab analyst of OxPhos.
  • Glutamine is a major energy source for cells of the immune system, which, when they become cancerous, are capable of being metastatic, spreading cancer far and wide in the body. (I added emphasis with bold italics to the two sentences on this.)

Here is the passage:

Although many tumor cells have active TCA cycles and might appear to respire, in that they consume oxygen and produce CO2 and ATP in the mitochondria, I will present data showing that this is pseudo respiration in some cases. In other words, pseudo respiration has all the characteristics of respiration, but does not involve ATP synthesis through OxPhos. I propose that this apparent respiratory energy is derived from amino acid fermentation. Just as tumor cells ferment glucose in the presence of O2, some tumor cells also ferment glutamine and possibly other amino acids in the presence of elevated glucose and O2. ...

The neutral amino acid glutamine is readily taken up into cells through simple uniport mechanisms [15, 18]. Glutamine can serve as a major source of metabolic fuel for generating ATP through TCA cycle, substrate-level phosphorylation when OxPhos is deficient [42, 44]. Glutamine is also anapleurotic in replenishing metabolites for the TCA cycle [59, 65]. We recently described how cancer cells could generate energy through mitochondrial fermentation and substrate-level phosphorylation in the TCA cycle using glutamine as a substrate [44, 58, 66] (Fig. 4.8). Glutamine is also a major energy fuel for cells of the immune system [67]. As myeloid cells can be the origin of many metastatic cancers following fusion hybridizations, glutamine becomes an important fuel for driving metastasis [66, 68] (Chapter 13). Indeed, targeting glutamine can significantly inhibit systemic metastasis as we have shown [69] (Chapter 17). ...

It is well documented that glutamine enters the mitochondria where it is rapidly metabolized to glutamate by mitochondrial glutaminase [18, 83]. Glutamate is then metabolized to α-ketoglutarate through either a transamination reactions with aspartate or alanine as products or through the action of glutamate dehydrogenase [15, 18, 65, 83].

The bottom line is that plenty of amino acids, like plenty of sugar, can keep cells that can't do OxPhos well-fed. Protein is made of amino acids. My hypothesis to be tested is that the sudden bursts of sugar-abundance in the body generated by eating easily-digestible carbohydrates and the sudden bursts of amino-acid abundance generated by eating the concentrated protein in meat and other animal products can improve the environment for cancer cells. In my own practice, I have quit eating sugar and other easily-digestible carbohydrates, which have many other bad effects as well, and have cut back on milk and meat without eliminating them.

Thomas Seyfried makes another important claim: that cancer cells will have trouble metabolizing fats and the ketone bodies made from body fat during fasting, especially given the low blood-sugar levels during fasting. Again from Chapter 15:

Because tumor cells ferment rather than respire, they are dependent on the availability of fermentable fuels (glucose and glutamine). Normal cells shift metabolism from glucose to ketone bodies and fats when placed under energy stress. ...

Ketone bodies and fats are nonfermentable fuels in mammalian cells. Tumor cells have difficulty in using ketone bodies and fats for fuel when glucose is reduced.


Conclusion: Races that Cancer Can Win and Races Cancer Can't Win

If cancer cells have already made the adjustments to switch over to fermentation, injuries that deprive cells of oxygen by interrupting blood flow could give cancer cells an advantage. But fasting, which shifts the nutrients available to cells toward fats and ketone bodies, should give an advantage to normal cells. 

More generally, eating less should be harder on cancer cells than normal cells. Many people bemoan the fact that when they lose weight, their metabolism becomes more efficient, so that they burn fewer calories in a normal day. But there is a silver lining to an efficient metabolism: if normal cells are running their metabolism at maximum efficiency, getting a lot of energy from a relatively small amount of food, cancer cells that can't do OxPhos won't be able to keep up. And if cancer cells die because they can't keep up, the day you die can be put off. 


Don't miss these other posts on diet and health and on fighting obesity:

Also see the last section of "Five Books That Have Changed My Life."