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