The lead article in the NY Times Magazine on Jan. 1, 2012, no doubt timed to coincide with the annual bumper crop of weight loss resolutions, is a poignant and personal essay by Tara Parker-Pope suggesting that we are, in essence, at war with our bodies over weight control.
Ms. Parker-Pope refers candidly to her own weight loss struggles, and to those of her late mother. Her personal conclusion is both hopeful and wistful:
I wish she were still here so I could persuade her to finally forgive herself for her dieting failures. While I do, ultimately, blame myself for allowing my weight to get out of control, it has been somewhat liberating to learn that there are factors other than my character at work when it comes to gaining and losing weight.
On these personal matters, Ms. Parker-Pope and I emphatically agree. I don't know her, or her mother -- but have known many patients just like them. I have witnessed firsthand the denigrations they have suffered, the humiliating additions of insult to the injury of the obesity itself. I have, in each such instance, worked hard to help my patients overcome and understand -- to forgive themselves above all. To know, and to feel, that it isn't their fault.
On these personal matters, Ms. Parker-Pope and I seem to agree. But we seem to differ somewhat on the implications of the big picture, and on what questions we should be asking.
Ms. Parker-Pope asks, in essence, how and why do our bodies conspire against our efforts to lose weight and keep it off, and what can we do about it? She infuses her discussion of the body's robust resistance to lasting weight loss in the aftermath of obesity with the insights of experts, and of others -- like herself -- burdened by both that vexing reality and an excess of pounds.
We do, indeed, know, that there are more than 30 specific genetic polymorphisms associated with a propensity for weight gain and obesity -- and that these same genes conspire against lasting weight loss. We do, indeed, know that fluctuations in leptin, ghrelin, PYY and an affiliated litany of other hormones and neurochemicals similarly facilitate weight gain and forestall weight loss -- in some more than others. We know that ethnic and genetic variation can translate into at times dramatic variation in susceptibility to weight gain and the capacity for weight loss.
And we do, indeed, have at least early evidence of potentially long-term physiological adjustments in the aftermath of weight gain and loss that goad the body into regaining what was lost, and "defend" it against losing what was gained.
Ms. Parker-Pope cites such evidence, and concludes the following: "This translates into a sobering reality: once we become fat, most of us, despite our best efforts, will probably stay fat... Clearly, weight loss is an intense struggle, one in which we are not fighting simply hunger or cravings for sweets, but our own bodies."
If we are fighting our own bodies, we have cause to ask who started it, and where it's likely to end. My principal objection to the worldview in Ms. Parker-Pope's essay, and in the labs of those looking to account for obesity in our genes, is that our bodies instigated this belligerence. I beg to differ.
Throughout most of human history, calories were scarce and hard to get, and physical activity was unavoidable. It is no fault of our bodies, long adapted to the exigencies of such a world, that we have devised a modern environment in which physical activity is scarce and hard to get, and calories are unavoidable. We are the proverbial fish out of water.
That overused and consequently trite metaphor is a window to a whole world of understanding.
Imagine scientists dedicated to understanding the predicament of fish out of water. Imagine looking for an explanation for their common distress, and for any appreciable variations in it (not all fish asphyxiate at exactly the same rate; not all recover from near-asphyxiation at the same rate when returned to the wet) in the genes or hormones of the fish. The answers would be there, of course -- fish have genes that cause embryonic fish to manufacture embryonic gills. Ostensibly genes that provide a recipe for gills are genes that account for the whole fish-out-of-water debacle.
But little gained from the advance of such scientific inquiry could supplant the fundamental understanding derived from seeing the big picture, and reaching the self-evident conclusion: Fish don't belong out of water. The responsible genes -- and gene products (e.g., hormones, neurochemicals, enzymes, etc.) -- would be the very genes and gene products responsible for nothing less than... fishiness. How many fish-out-of-water genes would we need to elucidate before recognizing this?
With unique Homo sapien arrogance, we speak of a world populated by contrivances natural and "man made" as if we are a force apart from nature. We are not. We, too, are a part of a system larger than ourselves. We, too, are creatures. We, too -- like fish -- are adapted to a native habitat, imperiled when we sojourn too far from it.
Ms. Parker-Pope notes the following: "What is clear is that some people appear to be prone to accumulating extra fat while others seem to be protected against it."
This is no doubt true, even though only some of the underlying mechanisms are as yet understood. But here, too, there is a risk of trees obscuring the forest.
Well over 65 percent of adults (and an alarmingly high percentage of children) in the U.S. are currently overweight or obese, and at least one well-conducted projection indicates that before long, all of us will be (but for a rounding error). Despite the persistent importance of hunger and famine in the world, there are now more overweight than hungry humans on the planet. The CDC projects that by mid-century in the U.S., as many as one in three of us will be burdened by diabetes.
Studying our variable vulnerability to these epi-phenomena would be a bit like studying variations in the tendency to drown among passengers on the Titanic. Among the Titanic's many victims, some drowned before others, and a reason might have been discerned in their ethnicity or their socioeconomic status. (These are associated with variations in the obesity rate as well.) But these would have been surrogate markers for something more relevant: Poorer people were on the lower decks that flooded first.
It might not be entirely pointless to account for inter-individual variation in the tendency to drown, but it would carry the hazard of distraction from the big picture, and the key observation: The ship was sinking. There was some variation in the peril, but it was variation of degree, not kind. The true fault lay not with variations in the passengers, but with the fate of the vessel.
With regard to obesity and attendant chronic disease, we are similarly all in the same sinking ship. We are staring over the bow at universal obesity. We are gazing over the gunwales at a roiling sea of diabetes, stroke, cancer and heart disease.
Alas, Ms. Parker-Pope writes: "The view of obesity as primarily a biological, rather than psychological, disease could also lead to changes in the way we approach its treatment." Perhaps so, and certainly I have colleagues who both believe this and are committing their careers to the fulfillment of this particular promise.
But in my view, obesity is neither a psychological nor a biological disease, if it is a disease at all -- it is a social disease.
Better still, it's not a disease at all -- no more of a disease than drowning. Drowning isn't about bodies behaving badly -- it's about bodies behaving normally in a place they don't belong. We are drowning in a sea of highly-processed, hyper-palatable, betcha'-can't-eat-just-one calories.
Are our bodies with us, or against us? Do they conspire to make and keep us fat? Our bodies, like polar bear bodies, or cuttlefish bodies, or python bodies, are shaped by primordial forces. There is no battle or belligerence in play here; there is only action and reaction. Our bodies' adverse reactions are indicative of an environment mightily at odds with our native traits and tendencies.
It's true, of course, that our bodies hang on to weight, and not all with identical efficiency. It's true that our bodies make weight gain easy, and make weight loss hard (for some more than others). It's true we have genes and hormones and neurochemicals underlying all of this.
But it's also true that throughout most of human history, calories were scarce and hard to get and physical activity was unavoidable -- and we are adapted to that world. Our plight is no different from that of fish out of water, of polar bears in the Sahara. Would the bodies of those bears be with them, or against them? The question is silly. They would simply be polar bear bodies, adapted to polar bear environments -- and maladapted to all else.
One of the key dilemmas with which Ms. Parker-Pope wrestles is that a body that has gained and lost weight requires fewer calories than a body of the same size that hasn't at one point been heavier. This is a genuinely important revelation -- a body exposed to weight loss and gain fights to hang on to weight with enhanced vigor.
The mechanisms underlying this are a work in progress, but the concept is less unfamiliar than it seems. A very similar physiologic reaction is why in general we don't get chicken pox, or measles, twice. It's why vaccination works.
When we are first exposed to an unfamiliar virus, our defenses can be overcome -- and we can get awfully sick. In the aftermath of such an exposure -- either to the virus itself, or an attenuated version in a vaccine -- our immune system learns to recognize the threat. Having seen the virus once, it is prepared for it the next time -- with defenses in place for a rapid and vigorous response. Forewarned is forearmed, quite literally, with antibody-generating memory cells.
It stands to reason that the historically common threat of starvation would exact a nearly identical priming response -- with significant weight loss the first time, but far less with subsequent exposures. The body would be forewarned and forearmed against starvation by the means at its disposal, just as it would be against a return of the measles virus. The responses are exactly analogous -- it's just that we appreciate the one, and lament the other. Perhaps we have trouble understanding what we wish weren't true.
Ms. Parker-Pope notes that the variant of the FTO gene associated with both obesity and Type 2 diabetes is "surprisingly" common. But why the surprise? Obesity and type 2 diabetes are common -- so it stands to reason that our genetic vulnerability for them must be as well. The percentage of fish with genetic variants associated with asphyxiation out of water would be extremely high, and entirely unsurprising. Again, the big picture tends to elude us.
Ms. Parker-Pope rightly points out our excessive emphasis on willpower. We can see its limitations if we reverse places with those fish. Will power is the equivalent of diving under the water and committing to just holding your breath. There is only so far that it can take you.
Of far more fundamental utility is "skill"-power. That's the weight-control equivalent of scuba gear -- the knowledge, aptitude-based capacity to devise solutions to the specific challenges of the environment. But even the combination of willpower and skill-power fall short of the true answer: modifying the environment so that health just tends to happen. Getting out of the water and living on an island where the breathing comes easy.
In her article, Ms. Parker-Pope refers to the National Weight Control Registry, a valuable resource that chronicles and collates the experiences of the thousands -- small minority though they are -- that overcome all obstacles, and both lose weight and keep it off. My own experiences with patients at the end of the bell curve where lasting weight loss is all but impossible have inspired me to create the Registry's counterpart, the National Exchange for Weight Loss Resistance -- as yet, still quite nascent. My hope is that over time, the Exchange will foster both understanding and a capacity for overcoming that may allow some of its members to migrate to the Registry.
Ms. Parker-Pope comments: "Weight-loss scientists say they believe that once more people understand the genetic and biological challenges of keeping weight off, doctors and patients will approach weight loss more realistically and more compassionately." Amen to that. But let's beware the hidden peril of that genetic and biological understanding. It can be hard to see what's going on all around you while looking through the lens of a microscope. We are notoriously prone to missing the big picture.
Efforts to find health despite an environment at odds with the native inclinations of our bodies will, at best, play out like the painful collision between unstoppable force and immovable object. There is a better way.
We must alter the environment to favor healthy weight -- and we must prioritize the prevention of weight gain and obesity in the first place, because the problem is extremely hard to fix definitively once it develops. This is analogous to all of the infectious diseases we can prevent with strategic use of vaccines, but find awfully hard to treat effectively. In some cases, such as rabies, prevention is almost perfectly reliable, and treatment almost perfectly hopeless. Our struggle with weight is not on entirely unfamiliar ground.
Can we prevent weight gain and obesity? The answer is self-evident in our rear-view mirror.
Obesity has become epidemic over the past half-century only, and was relatively rare throughout history before that. In our native Stone Age habitat, it likely didn't exist. There's our answer. Since our genes and hormones have not changed appreciably in 50 years, we must attribute the advent of epidemic obesity to environmental change. With the right environmental reverse-engineering, all obesity could be prevented. It stands to reason that even a moderate array of environmental modifications would go a long way toward fixing the problem at its origins.
Debate about whether our bodies are with or against us evokes innumerable historical scenes of battle in which competing armies with competing beliefs both invoke God -- and seek to have the Almighty on their side. Abraham Lincoln famously redressed this hubris by praying humbly that we would be on God's side.
Are our bodies with us or against us?
There is no good answer, because it is the wrong question. Our bodies are what they are -- adapted to their native habitat, no less than those of other creatures for whom we find this self-evident. We have devised a world in which our bodies all too often simply cannot thrive. There is no fault, no battle. There is simply action, and reaction. As fundamental as the laws of physics. As plain as a Paleolithic day. As blatant as the plight of polar bears in the Sahara.
We seem inclined to plead with our bodies to be on our side, but would be far better served by conspiring to be on their side. As we seek explanations in our innermost interstices for why the reactions of our bodies make sense, we must not be distracted from the actions of the body politic required to establish an environment -- in which they actually do.
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