Monday, July 22, 2019

Todd's Review of Range by David Epstein



Range: Why Generalists Triumph in a Specialized World
by David Epstein
New York, Riverhead Books, 2019

Review by Todd I. Stark

This is a beautifully written and well justified discussion of the various specific things that are not taken into account by the widespread cultural emphasis on early specialization for success and our popular model of performance in terms of domain-specific expertise.

This takes the form of a single conclusion which I would paraphrase as: "we need to be able to play and explore widely and to color outside the lines for a while in order to become very good at solving the difficult problems we later encounter.  But our cultural obsession with specialization pushes counter to that." 
There is a constant tension of the author's confidence in his conclusion that generalists are uniquely valuable and desperately needed and his recognition that he is fighting an almost Quixotic uphill battle against powerful cultural trends and incentives for specialization. 
What he means by specialization and the factors closely tied to it:
  1. Head Start: Encouraging children from an early age to narrowly pursue things they seem talented at or have an interest in.
     
  2. Domain-Specificity: Training with heavy emphasis on the specific narrow range skills we know we will need in the target environment and assuming far transfer of skills from other activities will be limited or non-existent.
     
  3. Disciplinary Focus: Viewing learning as consisting of accumulating facts and theories specific to a particular field or subfield of study in order to become highly skilled at working in that narrow field.
     
  4. Persistence:  The idea that we should identify a passion early and stick with it no matter what because it’s what we’re good at and enjoy and so can become successful at it if we manage to persist.
     
  5. Fast and Efficient Short-Term Learning:  The assumption that we are learning better when we feel familiar with the material quickly and that we are then learning more efficiently. 

     
    Against those powerful and popular specialization factors, Epstein presents several compelling lines of evidence:
     
  1. Domain-Specificity varies with Kind vs. Wicked Learning:  The argument for early specialization and domain-specificity is based on the observation that we need a long period of deliberate practice to accumulate the patterns and skills specific to performing in that specific activity and that practicing or exploring other activities is unlikely to do anything helpful for our performance in our specialty.  Epstein counters that on closer inspection we find a crucial distinction between different kinds of domains and learning environments, where in some of them deliberate practice reliably makes us better but in others deliberate practice either helps much less or can even make us perform more poorly under some conditions.  So not all domains or learning environments are equally specific and the head start is not equally helpful in all activities. 
  2. Creative Performance comes from early exploration and interdisciplinary learning:  Given the domain-specific view of expertise we tend to assume that in order for someone to perform at a high level in any activity, since they need expertise, they need to specialize in that activity.  Epstein counters that when we focus specifically on creative performance, we find that deep expertise can be invaluable but is not enough.  In order to come up with truly novel solutions to problems we need to make use of analogies that cross different domains while sharing deep structural similarities.  That means being familiar with a wider range of ideas and ways of thinking than just those in our specialty, and so Epstein says creative performance is found more in people with broader backgrounds.  Epstein argues that outstanding creative performance also tends to be associated with early exploration of different activities more than with early specialization. 
  3. The Efficiency We Perceive from Narrow Immersion is Very Often Illusory: We tend to assume that when we feel more familiar with the activity or material that we are learning it.  That’s part of the strong intuitive appeal for immersion in an activity comes from, it feels like we are learning more when we are more immersed.  Epstein argues that the evidence from learning research show quite often exactly the opposite, that the learning we think we are doing under conditions of immersion is either much less or much shorter lived than we assume.  Robert Bjork’s concept of “desirable difficulty” in learning and the evidence base behind it plays a central role in this argument.   This, Epstein argues, tells us that “slow learning” which helps us make new connections between a wider range of experiences is much more conducive to learning in the long run than fast, efficient learning from immersion in a narrow subject matter.
  4. Match Quality is Not Necessarily the Same as Early Passion: Part of the argument for early specialization is based on the assumption that people have certain interests and talents from early on and if they can find something that matches them well and start early, they can align their passion with a successful career in that activity.   Epstein argues that what we know about lifespan development tells us that people’s passions are not so fixed or narrow and finds a number of cases of exceptionally successful people who spent their lives exploring and trying different things before finding a match that was truly satisfying and successful for them.   
Range is an appeal to encourage exploration in our lives from early on and for experimenting and experiencing broadly in our learning, even though it may seem to be inefficient or slow.  Epstein does not deny the immense value of long deliberate specialized practice in “kind” domains or the value of having deep specialized experience in some areas, but he has also made a passionate and well-argued case for making better use of a completely different dimension of performance.  A dimension rooted in longer term developmental outcomes, more exploratory or playful learning, and an ongoing search for ever better matches between our interests and abilities and our activities. 

Review on Amazon:
https://www.amazon.com/review/R3I57PTPZXSYU4/ref=cm_cr_srp_d_rdp_perm?ie=UTF8

Friday, January 29, 2016

Rate of weight loss is not a good predictor of long term success

The Problem of Obesity:  Personal efforts to combat it

Rate of weight loss and its relationship to long term success

Linked below is just the latest among 4 studies I've reviewed from about 2000 to the present that appear to support the conclusion that the rate of weight loss does _not_ have an intrinsic effect on long term maintenance success.  That is important to know especially because a number of sources, some of them authoritative, promote that heuristic, such as claiming that people should lose weight at a particular gradual rate in order to maintain loss.  Fitness programs sometimes promote the reverse idea, that people can only succeed if they see dramatic results to encourage them. 

However the research seems so far to be telling us that rate has no intrinsic relationship to maintenance success in either direction. 

Collectively to me these studies don't seem to say that fast is better, and they don't seem to say that slow is better. 

I think it means that your choice of strategy if you are deliberately trying to lose and maintain weight for some reason should not be based upon rate by itself.   The heuristics of "gradual is better" or "fast is better" are very weak and should be rejected and replaced with more specific strategies that apply either more generally to people, or which have been calibrated more specifically for your own situation.  Haphazard use of the rate heuristic in isolation is implied by these studies to be very likely unhelpful.

Instead we should think about whether we are able to sustain the changes needed to lose the weight long enough to achieve our objectives, and consider how we are going to make the transition to maintaining a different body composition. 

Are we relying entirely on our enthusiasm to lose weight to trade off effort for early success, for example.  That's where fast early success can fail us, as our enthusiasm wears off and we find the things we were doing initially are becoming more difficult.

Conversely are we relying entirely on the assumption that gradual change is easy and sustainable?  This is shown to not neccessarily be the case.  People often find gradual change increasingly difficult to sustain eventually just as they find rapid chagne increasingly difficult to sustain. 

It isn't the rate itself that makes a difference, that impression seems to be partly a matter of us spreading weakly investigated but intuitively appealing information, and perhaps the compelling nature of the metaphor of rate and effort over time, where we tend to imagine something like trying to run up a hill and then falling back down vs. travelling over a gentle slope.  That metaphor breaks down apparently when it comes to weight maintenance over time.

(Vink et al., 2016)
http://onlinelibrary.wiley.com/doi/10.1002/oby.21346/epdf

Previous work with similar results:

(Nackers, Ross, and Perri , 2010)
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3780395/

(Das, Saltzman, Gilhooly, et. Al, 2009)
http://onlinelibrary.wiley.com/doi/10.1038/oby.2009.120/full

(Astrup and Rossner, 2000)
https://www.ysonut.fr/sites/fr/pdf/Ysodoc/C0103.pdf

Thursday, August 06, 2015

Fatness and Obesity: Framing the Problem

Fatness and Obesity - Framing the Problem
The Big Fat Problem refers to both obesity and fatness, but I want to make a distinction from the start between those subproblems because while they overlap they don’t always go together.

For our purposes here, I am going to define obesity as a pathological condition of visceral body fat associated with various metabolic diseases. The problem of obesity is obviously closely related to the problem of fatness, it a subset of that larger problem. But a lot of people are fat without being unhealthy and a lot of people are unhealthy without being fat, so fatness itself is not necessarily pathological, even if we sometimes find it unappealing or undesirable.

The causes of fatness also overlap heavily with the causes of obesity, but in the case of obesity taken to an extreme pathological degree in a way that impacts our health as well as our aesthetics.
1. Different Kinds of Emphasis: Thriving, Health Risk, Fatness, Fitness


The distinction between obesity and fatness is important because we can sometimes do something beneficial for our health without necessarily making the big changes we might prefer to make in our appearance. People can also alter their appearance sometimes without necessarily improving their health very much. Focus on thriving, focus on health risk, focus on fitness, and focus on fatness are four different ways of thinking about these related problems. The situation is complicated by bringing fitness into the picture, as health enthusiasts understandably want to do. I suggest that it does make a difference to our long term success whether we approach the Big Fat Problem from the perspective of thriving, health risk, fatness, or fitness. Of the four kinds of emphasis, I suggest that long term success depends to some large degree on how much we focus on thriving in particular. Fatness, fitness, and health risk are important but they don’t motivate us robustly in the same sense as our desire to thrive.
2. The Obesogenic Environment


Since obesity was rare until relatively recently, and it is unlikely that significant changes in the stable aspects of our heredity have occurred in that period, it is generally assumed (with good reason I think) that the current prevalence of obesity is driven largely by changes in our environment. As opposed to the most heritable aspects of biology changing for example. The idea is that we have not become a new and fatter species (homo obesicus?), but we are still the same species living under conditions that create vulnerabilities for our existing genes.

Since it appears that prior to modern environments obesity was relatively rare, it seems reasonable to assume that the incidence of obesity is being driven by the relatively greater availability, variety, palatability, and reward characteristics of food, our relatively more sedentary lives, and perhaps some failure of our self-regulatory mechanisms to compensate for those environmental changes because of various changes in the way we live. Diet authors have made some far more specific claims and I want to address the strengths and weaknesses of those. But for now I just want to affirm that the “obesogenic environment” theory of obesity is probably a very good starting point for analysis. The idea is that our body is well tuned to tend to regulate itself under a variety of conditions, but we have created particularly extreme conditions for ourselves that in some sense bypass those regulatory abilities.
3. Mismatch Theory
Since the problems of obesity and fatness are very complex, I think it is helpful to find a way to think about them in a general way, to have an overall framework. The concept of an obesogenic environment provides us with a good start. For increasingly many of us our environment has come to bypass the ability of our body to regulate its storage of energy, resulting in the problem of fatness. That fatness in turn often becomes a problem for health, resulting in the problem of obesity.

Why has our environment become increasingly obesogenic? Perhaps the most general and plausible theory that brings the most observations together under a single umbrella is the mismatch theory. The mismatch theory says that human biology and human culture both evolve, but at very different rates. The genetic composition of organisms  is refined over time by Darwinian processes for particular ways of adapting to environments. The epigenetic composition of organisms is altered by the environment and behavior of our more recent ancestors.    When environments change very rapidly compared to those Darwinian effects on our genome, the previously adaptive functions of the organism can become maladaptive for the new environment .  The mismatch model is most centrally about differences between Darwinian adaptations and current environments, but that doesn't negate the possible significance of other effects that may be important  factors in obesity, such as epigenetic inheritance from our parents.  This model is particularly helpful as a very high level organizing principle for a very large and complex set of factors that lead to metabolic disorders. 

In a sense, human culture is a part of human biology, it is part of what allows us to survive, reproduce, and thrive, when it supports the needs of our biology. Since culture evolves more rapidly there is also a distinct possibility for culture to evolve in such a way that it no longer supports human biology in the same way. Our culture can outpace our genes in some ways, resulting in areas of mismatch between culture and biology.

Mismatch theory is very broad and very powerful, which also means we should be careful about applying it too casually. It would be easy to see every aspect of the obesity problem in terms of mismatch, whereas there may be factors that are better seen in other terms. However as a framework for troubleshooting, if we keep its limitations in mind, I think the mismatch theory provides us with our best starting point.
4. Problems of Comfort and Consumerism
During the latter 20th century we got increasingly fat and increasingly unhealthy at a rapid pace and it is useful to view that as a result of various aspects of our cultural environment changing rapidly compared to various aspects of our genome, which then becomes maladaptive for our current environment.

Given that framing of the problem, the big question becomes which aspects specifically of our culture and our genome are in conflict to cause the environment to become obesogenic? That’s where the most intense differences of opinion about The Big Fat Problem seem to arise. Did we get fatter because we started eating more grains? Did we become fatter because we started eating more sugar? Did we get fatter because the physical demands of our lives decreased to make us less active? Did we become fatter because more food is available and we just can’t help eating it?

Part of my framing of the solution is that people who succeed at maintaining a healthy weight after being obese have effectively created a local environment for themselves that protects them from the obesogenic aspects of their environment, and without forcing themselves to constantly fight their own biology or their own desires.

In order to create this sort of local environment, we have to understand what about our lives is most mismatched with our ability to regulate our energy storage. Is it the sorts of things we are eating? The activities we engage in? The nutritional quality available to us? The amount of food available to us? The way food is marketed to us? The level of stress in our daily lives? The amount of sleep we get? The kinds of bacteria that live in our body? These ideas have all been proposed and any and all of them (and more) can be argued to be plausible factors. I want to insert a caution here about being too confident that we have identified the problem by identifying any of these particular aspects of our environment. It seems to me that sort of thinking tends to lead to ineffectively narrow strategies.

One way of keeping our perspective on troubleshooting rather than false solutions is to frame the problem in a very general way. I’ve suggested that the obesogenic environment is one very general framing. Mismatch between culture and biology is a further refinement of that thinking. A third suggestion I would make is to view mismatch in terms of the twin overall trends in culture toward comfort and consumerism.

These dual trends of comfort and consumerism are both associated with affluence on a grand scale. As wealth has increased in various parts of the world, so has the availability and variety of food and the reduced need for hard physical work. At the same time, the economies that drive that wealth are typically themselves driven by constant efforts to increase profits by producing more at lower cost and selling more. These broad trends both have many problematic implications for a species that has evolved in various ways to prefer and exhibit efficiency in its use of energy whenever possible. This is, broadly speaking, where I think the mismatch problem becomes obesogenic. I suggest that these are the aspects of our environment that we have to be most careful to protect ourselves from.


5. The Pivotal Calorie - Quantity vs. Quality


I’ve offered a broad framing of the problem of obesity in terms of specific aspects of modern culture that are mismatched with our stingy biology and create an environment that tends to make us fatter. A final level of specificity in framing the problem is needed in order to come up with specific ways of changing our behaviors and environments to be healthier. To do detailed and specific troubleshooting of our own situation, we need to have an accurate sense of how cultural mismatch actually impacts our behavior, nutrition, and metabolism. What sorts of things should be looking at in order to understand how our environment is affecting us and make effective and useful changes?
Calories In


Consider two facts about intake and fatness:

1. Population increases in obesity coincide with people eating more across those populations.

2. Individual increase in fatness does not always coincide consistently with people eating increasingly more.

A lot of wasted effort has been invested in arguing over which of these two facts is more important and a lot continues to be wasted.

Authors have devoted entire books to arguing about whether or not we should be monitoring calories or simply eating certain things vs. others.

The polarization over that question has far outstripped its usefulness, so for the record I want to try to put this question into some perspective here.

In recent years a number of authors have tried very hard to revolutionize our understanding of the problem of obesity by framing it as hormonal rather than in terms of energy balance. These authors argue that traditional weight loss solutions involving restricting calorie intake have failed because the problem is not one of how much energy we take in but of how our body uses that energy. The popularity of this view can be traced largely to Atkins, Taubes, and through most variations of the diet advice promoting high protein, high fat, low carbohydrate, low sugar, low glycemic, and “paleo” strategies (especially the animal-based ones).

Statistically, however, the first fact is undeniably the more important. When we look very closely at physiology for brief periods it appears that people can become fatter to some degree without eating more, but that does not seem to be a big part of the obesity problem at a population level. Some authors have denied that the second fact is even possible to any degree that impacts health, but I am going to stipulate the possibility here for the sake of argument.

I don’t think the problem of whether hormonal effects might make us more efficient at metabolizing vs. storing fat is terribly consequential, since the putative “fat burning diets” (usually high fat ketogenic diets) that people have heavily promoted are not sustainable for most of us anyway. Most of us don’t thrive on a ketogenic diet in the long term, so the claim that it is a solution to obesity has often been vastly exaggerated.

Further, for the more reasonable (less restrictive) versions of “hormone balancing” strategies, it doesn’t really matter whether they provide their benefit by altering metabolism or via helping us eat less.

What does matter is whether we are viewing the problem in a realistic way that lets us do useful troubleshooting. If I’m trying to lose weight or maintain a weight and I specifically avoid monitoring certain things because I’ve adopted a theory that disregards those, I could very well be ignoring very valuable resources. For example if I’ve adopted the view that “calories don’t matter” and I’ve committed myself to a particular diet, and I find that I’m gaining weight on it or that it is becoming increasingly hard to sustain, I’m not going to have any idea why I’m having a problem or what to do about it because I’m not monitoring important variables that I could be adjusting. I have to rely on the heuristics provided by the authors who promote that diet, and those are almost always anecdotal and based on selective experience of people who are similarly committed to that strategy. If I’ve adopted the view that “calories are the only thing that matter,” I could very easily find myself in the same unfortunate situation, not monitoring some of the variables that could be used to improve my success.

We sometimes draw simplistic and unhelpful conclusions from each of the above facts, resulting in endless and largely useless debates over whether quantity or quality of food matters most to obesity.

If we do follow these debates, seem at first to discern roughly two camps: (1) the “calories in/calories out” camp that seems to argue that the quality of food doesn’t matter and fatness is entirely about how much energy we take in and expend, and (2) the “metabolic advantage” camp that seems to argue that the amount of food we eat makes no difference to fatness so long as we eat the right sorts of things.

I’m not entirely sure whether anyone actually believes either of those extremes are true, outside of heated debates perhaps, but I’m pretty sure they are both exaggerations. Quantity and quality of food both matter to fatness and to health and thriving in general.

Since more obese populations eat more than less obese populations, we are often tempted to blame obesity on eating more and exhort each other to count calories and take in less food. Most attempts to simply eat less are a dismal failure in the long run.

Since we are relatively bad at monitoring our own metabolic energy dynamics and since those metabolic energy dynamics change significantly from one set of conditions to another, we are alternately often tempted to blame obesity on how the environment is “breaking our metabolism.” Broad attempts to fix our broken metabolism and to invoke “fat burning metabolism” by eating in a certain way have not resulted in real sustainable solutions for most people who attempt them.
Calories Out


An important part of the metabolic energy dynamics picture is activity.

Consider two facts about activity and fatness:

1. Population increases in obesity coincide with decreases in activity.

2. Individual increase in fatness does not always coincide consistently with people getting more activity.

Again, as with food quantity and quality, we find a lot of debate over the calorie in terms of activity. Do we need to move more or eat less, or just move and eat differently?

If we were to accept the extreme quantity argument about fatness, and extend it to activity, we seemingly would be saying that people just need to “burn off” more than the calories they take in, and weight loss would simply and reliably follow. Trying to burn off calories to regulate weight is typically a dismal failure. People feel compelled to exercise in ways they don’t enjoy just to compensate for eating and they come to resent it. They also very often tend to eat more to compensate for the exercise, defeating the whole purpose. So the simplistic form of the quantity argument doesn’t extend to activity either, even though there is no doubt that moving more expends more energy in general.

If we were to accept the extreme quality argument about fatness, and extend it to activity, we seemingly would be saying that specially designed exercise programs can alter our metabolism in ways that make us leaner without affecting our intake adversely. This is in line with what many people selling fitness products do claim in their advertisements, but it doesn’t seem to be a real obesity solution for most people either.

Analysis by researchers seems to so far implicate intake rather than exercise per se in the population incidence of obesity. Populations studied so far did not become fatter simply because they moved less. The quantity argument about activity has not been supported in that respect. However sedentary living is undoubtedly one of the factors that makes fatness a problem. Activity has consistently been shown to be an important factor in maintaining healthy levels of body fat and being sedentary (sitting a lot) seems to be an independent risk factor apart from simply not exercising. So a sedentary lifestyle does seem to result in us becoming poorer at regulating our body fat and maintaining our health, even if it is not specifically because of “burning less calories.”
The Big Fat Problem


The Big Fat Problem is that increasing fatness is very difficult to reverse both in individuals and in populations once the trend is established, and eventually leads to the potentially serious health implications of obesity.

The problem is so difficult in part because it is a result of our biology being unprepared to compensate for the extremes of demands and temptations found in our environments. We can oppose it in various ways for a while, but long term success is relatively uncommon. The solutions offered to us tend to fall into conflicting extremes that work in the long term only to a very limited extent and lead to confusion and frustration.

What as individuals can we do about The Big Fat Problem?

What can be said about it that has not already been said?

1. We can emphasize thriving over aesthetics or risk or fitness. Whatever we do must be consistent with thriving amd not result in constant deprivation and distress for the sake of health or fitness or appearance.

2. We can learn to treat fatness as a developmental concern rather than a quick fix, since the long term is the more important and the more challenging time frame for addressing the problem.

3. We can learn to troubleshoot our own problem of fatness by better navigating the popular dialectics of quantity and quality or intake and activity

Saturday, July 11, 2015

Obesity - What is the real problem?


 

To me it seems critical that we get a realistic and accurate sense of the overall problem, since much of the difficulty is confusion regarding how to think of it in the face of seemingly conflicting information.  I am going to offer my understanding of the scientific consensus as a framework.   

 

For all the confusion we often have over various aspects of nutrition and fitness, I think there are a handful of principles that are particularly reliable based on the evidence we have so far.  

 

The reason so many people around the world have been getting so much fatter so quickly is that they are taking in more energy than their bodies need in order to be nourished and satisfied.  And they do this for reasons that they are mostly unaware of having to do with reward, preference, palatability, expectancy, reliance on cues, and satiety.  Let's call this the mindless surplus intake theory of obesity. 

 

As intuitive as it might seem at first, the mindless surplus intake theory of obesity doesn't have to be true.  There could be other reasons for our growing fatness.  Our bodies or environment might have changed to make many of us store fat more efficiently from the same amount of energy intake (the broken metabolism theory of obesity).  A number of authors in recent years have promoted variations of the broken metabolism theory.  The broken metabolism theory sounds scientific and some variations of it have been promoted with long lists of research citations or even with the limited blessing of some researchers, especially when it is combined with reasonable actionable advice as well.  In general though it seems to me that the "broken metabolism" theory itself has been pretty thoroughly falsified as a primary driver of obesity.  And that fact matters in some  important ways.

 

Our bodies or environment might also have changed to make many of us more impulsive about eating  and we have failed to compensate by exercising our willpower adequately (the gluttony theory of obesity).  Similarly, our bodies or environment might have changed to cause us to be less motivated to move and we have failed to compensate by exercising our willpower adequately (the laziness theory of obesity).  The gluttony and laziness theories are compelling to us individually because we have a strong intuitive sense of the importance of personal responsibility, and self-control is indeed a powerful factor in success across many endeavors.  However the laziness and gluttony theories exaggerate the role of deliberate self-control in the myriad decisions we make every day about eating and activity.  People successful at controlling their weight use their self-control not to make every decision deliberately but to create better habits for themselves and shape their environment to help them.  It is not a failure of willpower that drives obesity.  That fact also matters in some very important ways. 

 

Our bodies or environment might also have changed to cause us to need less food while still eating  enough to create a surplus (the inactivity theory of obesity).   Activity levels contribute significantly to both health and obesity, and especially to the maintenance of healthy weight, but we know the driver of obesity is mostly intake and that just moving more without also cutting back energy intake doesn't reverse weight gain in the obese in general.  This is almost certainly a major factor in both health and obesity, but it is clear from the existing evidence that it is not the primary driver of obesity.  The trend in fatness corresponds far more closely to changes in intake than changes in activity.  Also the experimental evidence shows activity being far more useful for maintaining weight loss than for simply "burning off calories" in most people, largely because we often tend to eat more to compensate for exercising.

 

In addition, more than one of these might be a factor.  But from my reading of the evidence patterns, the primary driver of obesity is now clear.   We have been taking in increasingly more energy than we need, mostly because we have been eating more than we would need to fuel our activities and nourish our minds and bodies.    And we have been doing this for reasons that do not involve the specific discretionary macronutrients we eat most of (e.g. carbs vs. fats), do not involve us simply failing at deliberate self-control, and do not involve us having inadequate knowledge of which diets are best for weight loss. 

 

What are these mysterious reasons for creeping intake if it is not eating too much fat or too much sugar or too much starch in particular as many authors have claimed?

 

  1. Our intake is regulated primarily by mechanisms of reward, preference, palatability, expectancy, reliance on cues, and satiety.  We learn what to eat and how much based largely on stimulus cues, what we expect from food, how palatable foods are to us, and how they make us feel.
  2. Our reward and satiety mechanisms are optimized for regulating our weight under natural stimulus conditions by relying primarily on volume and weight of food and secondarily on energy content.  We mostly tend to eat about the same volume of equally palatable and rewarding foods every day.  
  3. Our metabolism is optimized for efficiency of energy storage rather than for maintaining a stable weight.
  4. We are bad at estimating how much energy we need in order to be nourished and feel satisfied.
  5. We are bad at estimating how much energy we are taking in in order to compensate for well-engineered distortions of reward and palatability.
  6. We have come to rely increasingly on cues in our environment to determine how much energy we need and how much we are taking in
  7. We have come to increasingly exploit our reliance on cues in our environment in order to market food and health and fitness products, and this distorts the cues we rely upon so heavily
  8. We have come to increasingly rely on strategies which overemphasize small or irrelevant metabolic effects, rely on outdated theories, rely on willpower, ignore the long term, and in general are unsustainable and make us feel like failures when we can't sustain them.  

 

If my understanding of the scientific consensus is correct, the mindless surplus intake theory of obesity reflects it well and can be understood in more detail in terms of the satisfaction theory of intake regulation.   This says that we eat mostly what satisfies us because of the way the reward and satiety mechanisms work in our nervous system rather than because of metabolic or nutritional effects.   What gets "broken" in obesity in general is that we stop being satisfied with a nourishing amount of food and we keep eating even though we are taking in more than we need.  The reasons for this have little directly to do with willpower or carbs or fats and everything to do with the mechanisms of  reward, preference, palatability, and satiety.

Why is the problem of obesity so damned tricky?


  1. Why is the problem of obesity so damned tricky?

 

A lot of us are fat. Fatness increased dramatically in the 20th century, especially since the 1980's in the US.  We don't like being fat in general.  When it becomes extreme, body fat usually doesn't look good to us and can lead to health problems, diminished longevity, and restricted quality of life.  Some distributions of body fat are worse than others for health or for appearance, but at some point it eventually looks bad to us and detracts from our lives.  

 

  1. Just Theories are Well Communicated and Popular but Wrong

 

If we find fat so problematic, why haven't we simply found good solutions for it and begun to apply them?  Most people can lose some body fat temporarily by some combination of depriving themselves of some particular kinds of preferred foods, trying to force themselves to eat less,  and trying to force themselves to be more active.  Most people end up going back to their original body fat levels, or greater, after a few weeks, months, or years of that effort.    There is no lack of simplistic just theories about why this is happening:

 

Fat people are just lazy and not exercising enough self-control over their eating and exercise

Fat people are just gluttons who eat too much

Fat people are just eating too much carbohydrate

Fat people are just eating too much starch

Fat people are just eating too much sugar

Fat people are just eating too much fat

Fat people are just maintaining their weight at a genetic set point

 

Although each of those ideas is wrong in its own particular way, and they are each perhaps partly right in some sense,  it is the just part that is most wrong of all.  The just theory is a special kind of problem in itself that is part of the reason fatness is so difficult to address.

 

Here's my central claim: scientific consensus is not just a matter of certain opinions winning out over others, the problem of obesity is understood in broad form as a scientific consensus even though many the details are complex and some of our knowledge of the factors is undoubtedly incomplete.  There is a rough scientific consensus about various aspects of obesity across fields of physiology, nutrition, psychology, neuroscience, and medicine.  It is not just the confusing mess that appears in popular media.

 

I also claim: this consensus understanding is not what is published in most diet, fitness, and weight control books.  In fact, a sizable number of popular books on diet and weight control conflict dramatically with the scientific consensus, but are marketed as if they were new and revolutionary new findings.    This has contributed heavily to the confusion and so added to the problem. 
 
 


B. The Scientific Consensus is Poorly Communicated
 
In the stories that journalists tell to try to communicate their own interpretations of the obesity and health research, they have often engaged the science compellingly but not faithfully.  We now know some very useful things that are not well communicated, or are even ignored or denied by popular authors with their own agendas, or get lost in the media confusion:
 
  1. The theory that people can control their weight by exercising self-control at each eating or activity decision is simply wrong.  
 
No one has that much self-control against an environment that constantly tempts them.  The psychological study of self-control reveals that variation in impulsiveness is indeed a factor in all sorts of problems, including obesity, and that people can often learn skills to compensate for impulsiveness, but these do not rely on individual acts of self-control.  Self-control is always finite, and we successfully compensate for impulsiveness by not just exercising self-control in each decision, but also even more importantly by altering our environment and altering our habits so that we reduce the need to exercise our always finite capacity for self-control.
 
  1. All of the theories of specific  macronutrients causing  us to become fat are simply wrong.
 
The theories of metabolic advantages of particular diets (low carb, low fat, vegan, paleo, etc.) have all been falsified scientifically so far.  Obesity is in general at the population level not caused by everyone's metabolism being "broken" by certain foods nor is it "fixed" by eating certain foods. 
 
We know for a fact for example that low carb diets do not cause people to lose weight by any special "fat burning mode" as is often claimed in popular diet books.   We know that simply eating a lot of fat or a lot of sugar while keeping energy intake constant does not cause us to gain more body fat.  We know for a fact that the theory of obesity being caused by insulin levels rising due to eating  too much starch or sugar is simply wrong.  People become fat when they take in too much energy regardless of the source and they lose body fat when they take in less energy regardless of the sources they eat less of. 
 
That doesn't mean people respond equally to every kind of diet.  It's just that the reasons are not metabolic.  The reasons have to do with reward, satiety, and sometimes individual differences.  But the metabolic differences between different macronutrient strategies is based on thinking that has already been tested and falsified.  
 
Also  this wouldn't have to be true necessarily.  It isn't a logical necessity that foods have no powerful differential effect on absorption and conversion to fat and fat storage.  It's not just a matter of thermodynamics or conversation of mass and energy.  It is possible that our biology might have allowed us to take in some kids of nutrient, extract energy or chemicals from it, and excrete most of it without gaining body fat.  But it turns out to be false.  The reason is not conservation of mass and energy, the reason that our biology is particularly efficient in using nutrients and in storing the surplus energy. 
 
We might truly have discovered some  differential metabolic effects that prevent us from processing certain foods into fat (and that is exactly what many popular authors have claimed) but … it turns out that it doesn't seem to be true in general, and certainly not as a reliable  way to lose body fat permanently.  The small differential effects of nutrients on metabolism are sometimes used to good effect in short term efforts at bodybuilding and fitness, but they are not a reliable approach to obesity in general.
 
  1. Consequently, No macronutrient restriction strategy is a best practice diet for everyone. 
 
Framing the problem of fatness as if we  need to choose between popular branded diets is more often part of the problem than part of the solution.  Branded diets are generally based on a particular just theory.  
 
Debates over low carb, low fat, low sugar, low starch, low glycemic, high fiber, vegan, paleo, and so on are mostly based on asking the wrong question: "what specific food is making me fat?" 
 
Cutting out problematic "trigger" foods can be helpful for particular people, but not for metabolic reasons.  Also cutting out entire classes of food can help at least temporarily lose weight.  This is also not for metabolic reasons.  This is because we tend to reduce intake more than we compensate, at least for a while, when we cut out entire classes of food. 
 
Some of those strategies work better than others in the short run.  But it turns out with those macronutrient restriction strategies that it really doesn't matter which class we chose to cut out in the long run. 
 
People who successfully reduce intake by restricting carbohydrates and people who successfully reduce intake by eating vegan or by eating "paleo" are all losing weight because they are taking in less energy, not because of metabolic advantages. 
 
So long as we can sustain the calorie deficit with that strategy, we lose body fat.  That's wonderful for the people who end up with a strategy they can sustain, and we can find some success stories for many different strategies.  Strategies that restrict entire classes of nutrients end up being unsustainable for most people  in the long run though and the claims often made about any of these having unique metabolic advantages for weight control have been soundly falsified.  
 
  1. People do not regulate their weight to a particular inherited set point.
 
This is the opposite problem from the panacea solutions.  This one reinforces our tendency to give up.  Fatness and leanness often run in families, but not because our genes have a built in weight that we are fated to maintain.  It is because of all of the various factors that go into activity, reward, impulse control, individual metabolism, and habit formation, how those interact with specific environments, and because we often inherit things in addition to our genes.  Animals in their native ecological niche tend to regulate their weight very tightly and people who try to lose weight often end up back at the same weight.  But these are as much a result of stable aspects of their environments as stability in their weight regulation.  When we re-engineer out environments we end up altering weight regulation.  The efficiency of our biology and the stability of our dispositions are powerful factors in making obesity a difficult problem but they do not  make it impossible to solve. 
 
I'm going to try to do more than just add my own personal just theory to the already confusing and conflicting list.  What I'm going to try to do is navigate the available evidence to show what is going on and make sense of why the problem is so difficult and what people are doing when they do manage to succeed.

 

  1. The Backlash Culture Against Obesity Does More Harm Than Good

 

So the "obesity epidemic," as it has often been called, has led to a culture of backlash against fatness.  By that I mean a commonly shared negative attitude toward fatness and toward fat people.  We have mobilized mightily against the problem in all sorts of ways.  Some of those have unfortunately probably made the problem worse. 

 

The backlash against fatness might have been a good thing if it had led to a problem solving culture that recognized the biological, psychological, cultural, and economic dimensions problem realistically, helped us understand it, and began providing realistic solutions.  Obesity researchers have sometimes attempted to offer realistic solutions, especially focusing on preventing obesity in children where we can potentially have the most effect.   

 

But realistic problem solving is definitely not most of what has happened so far.   What we have instead is:

 

  1. The problem remains: most people who try to lose body fat end up going from diet to diet or from one exercise program to another , succeed for a while, and then give up.  Eventually many give up on the problem entirely as hopeless.  In effect, we often give up on ourselves.  This is especially true when we buy in to the popular misconception that obesity reflects a simple failure of willpower.  Fat people are often stigmatized as lazy and they feel like failures, which generally makes the problem worse rather than better.

 

  1. The food industry exploits the situation by creating and marketing niche "diet" and "health" products that supposedly address the problem but which rely on outdated theories, popular misconceptions, and strategically selective interpretations of research.  The market for high density rewarding "diet" foods for example was created to exploit medical advice to eat less food by eating less fat.  The advice was oversimplified and the new market for diet foods probably added to the problem significantly by exploiting it.  Their goal is selling more food product rather than improving health, which most often turn out to be conflicting priorities.     They become part of the problem by flooding us with false solutions and misleading information. 

 

  1. The fitness industry exploits the situation by creating complex dietary and exercise programs that are oriented to short term bodybuilding or fitness goals and then marketing those as solutions to obesity. 

 

  1. Popular authors tout their range of idiosyncratic interpretations and solutions, each trying to make sense of the confusion but they mostly end up increasing it.  Popular diet just theories by journalists and doctors very often end up inadvertently creating even more confusion.  

 

So the backlash culture in these various dimensions,  far from helping to lessen the problem, has exacerbated and perpetuated it in several specific ways:

 

  • It increases the difficulty of the problem for individuals psychologically, by fostering confusion and then discouragement and self-loathing.  By emphasizing willpower in unrealistic ways, and relying on solutions that require extraordinary short term efforts, we make people less able to succeed rather than more able to succeed in the long run.

 

  • It adds to choice confusion when we try to make decisions and are led astray by the marketing of product rather than decisions in our own best interests.  Unless things like "diet foods" and "bootcamps" and "extreme weight loss" are themselves actually viable solutions to obesity (which they are not in general) they become new sources of both confusion and discouragement.

 

  • It reinforces the epistemological problem of cynicism.  Thinking we are all scientific experts  who are well situated to simply choose between the popular diets and popular theories that seem most plausible to us prevents us from learning from the actual research and prevents us from moving toward more realistic solutions.  We become easy prey for every scheme that comes along. 

D. Science Cynicism and Overly Broad Mistrust of Expertise

 

Journalists writing about the problem of obesity have responded to this ongoing confusion by either claiming we don't know what causes obesity or by trying to promote a particular new finding.  The problem is very complex in some ways, but it is very misleading to say that we don't know enough about it to move toward better solutions.  The journalists who say we don't know the answer are a minor concern though, they are at least sincerely trying to be good communicators of the science and clear up the confusion.  The ones who are really dangerous are the grandiose prophets of false information. 

 

What we usually have is a theory that catches the interest of the journalist and then they confirm it by gathering information and telling stories that reinforce their own theory.  This is a compelling and powerful way to communicate, but it offers no assurance that they are getting the science right.  And while we sometimes find out about truly revolutionary ideas this way, as it turns out, these "sciencey" storytellers are most often getting as much of the science wrong as they are getting right.   

 

These "sciencey" journalists often end up asking bad questions and then we end up talking about the wrong things.  I think this is a big part of the problem and the reason I have written this book.  I hope to describe what we know about the problem of fatness without falling into the common trap of arrogance and confirmatory bias, but of course I can only argue my own perspective.  I could be wrong about the scientific consensus, but I will do my best to communicate it as faithfully as I can. 

 

The unconstrained confirmatory bias by journalists wouldn't be so bad by itself in some cases, since they do sometimes bring information to light that was not previously well known.  At least some people would benefit from some of this information.    But these folks often then read some scientific literature to try to bolster their articles and books and I feel they often do a hatchet job on it.  They can't reconcile their idiosyncratic theories with the existing evidence so they start claiming that the evidence that conflicts with their own theory was due to "corrupt researchers."  This ad hominem strategy has been a highly successful one for some authors, but it is an unfair way to argue and much worse, it plays into general cultural cynicism of science.  That part is extremely bad for the rest us.  It means we perceive the science as arbitrary or a matter of choosing sides based on what sounds plausible or what seems to work for some people.  It feeds the popular trend for imagining that everyone is naturally capable of evaluating scientific evidence by virtue of "common sense." 

 

What often happens, I believe, is that we end up mistrusting expertise, which is in itself a very serious problem.   That fact that we find so many false or misleading claims of expertise makes the problem of finding, trusting, and interpreting legitimate expertise even more of a challenge.    Nutrition and health sometimes involve on complex technical knowledge and interpreting rich patterns of seemingly conflicting evidence.  This kind of interpretative skill and knowledge is not something we possess as part of our "common sense."  It is something that requires not only understanding "critical thinking" in general, but also requires domain-specific knowledge in the specific fields in question. 

 

The backlash culture and especially cynicism of real expertise has fed bias and arrogance by various popular journalists who then set the tone for popular conversations in unproductive ways.  Although they may have a lot of charts and graphs and selectively cite and interpret a lot of research, rarely do journalists engage the research deeply and competently and systematically and put it into context.  Rarely do they make a distinction between different kinds of evidence and different quality of evidence in order to do a skilled job or drawing general conclusions from the existing science. 

 

The biggest problem with many of these popular authors is their grandiosity.  They think they've discovered a pattern that everyone else has missed or they have some limited success with some people and they proclaim to the world that they have the solution.  Grandiosity exploits uncertainty and cynicism to produce cults of misinformation that are self-perpetuating and extremely difficult to address with reasoning and evidence.  
 
 

Summary of Why the Big Fat Problem is So Tricky

 

Summary of broad factors making the Big Fat Problem so nasty:

 

Problem Factor
Class of Factor
Associated Bad Thinking
We tend to think in terms of simple actionable heuristics we can act upon when we make decisions.  What food is causing me to get fat, so I can stop eating it and lose weight?  What foods should I eat to lose weight instead?  Our need for actionable heuristics makes us especially vulnerable to just theories, and just theories of complex outcomes are typically wrong.  
Oversimplification
"Obesity is just a matter of eating more of … or eating less of  …"
The science is often distorted into oversimplified advice.  The scientific consensus relies on expertise to understand and is hard to communicate in terms of actionable steps so it gets lost in the confusion of just theories.   We end up systematically asking the wrong questions and arguing without regard to the existing patterns of evidence.
Oversimplification
 "One study constantly contradicts the previous one, so it's all really useless information, we should just pick the authors we agree with and follow their advice"
Our collective cultural assault on fatness has led to a backlash culture that makes things worse and leads to additional problems.
Unintended Consequences
"Being fat is really bad, stop being so lazy!  Just do this… "
Journalistic arrogance and widespread science cynicism exploit the problem of ubiquitous expertise
Knowledge Cynicism
"We're all scientific experts, including me!  Forget the scientific consensus, this sounds like a good way, follow me!"
"Sciencey" storytelling journalism
Poor science communication
"Telling stories about research and researchers is a great way to learn the science!  The details of weighing evidence are boring and irrelevant and people aren't able to handle it."
Industry interests driven by economic and business concerns that often end up conflicting with public health or individual interests of consumers
Economically Driven Consumer Culture
 "People citing research in their ads and branding their products for health are generally offering valuable new choices for us."