Part way through the holiday season either definitely is, or definitely is not, a good time to think about obesity.  Between family feasts, work-related parties, New Year’s Eve, and cold (well, cold for California) weather, calories always seem to pack in more tightly this time year – leading to the clothes fitting more tightly.

And, in the interests of full (plus size?) disclosure, I must note that, if only I could grow a decent beard, I could be a great Santa Claus.  I’ve got the hair color; the “ho, ho, ho” abilities; and the body-mass index for it.  This personal, and non-financial, conflict of interest has kept from writing or speaking about the subject, though not from thinking variously shaded thoughts about it over the years.  A couple of recent articles, of very different types, have led me to share just a few of those thoughts in this blog post.

In its December 15, 2012 issue, the Economist, to which I have subscribed for over 30 years, did a long “special report” entitled “Obesity” (here).  (It may be worthy of note that this was in the issue immediately before its overstuffed, end-of-the-year, holiday “double issue” – “do you want fries with that?”)  The report reviewed some of the science of obesity, its (very limited) treatments, its epidemiology, its physical and financial costs (though not the psychological or social ones), the roles of food companies, and some of the plausible policy options for dealing with obesity.   The comparative perspectives were particularly interesting to me – the problem is much broader (pun intended) than the “flyover” parts of the United States with Mexico, the Persian Gulf, and even China experiencing their own obesity epidemics.

The Economist’s special reports are usually on things like Mexico, France, the World Economy, Technology and Geography, India, Judaism, London, natural gas, and the Arctic – those being the topics for its other special reports in the second half of 2012. The attention paid to this topic was striking . . . so was the shortage of easy solutions.

So I want to talk a bit about science and the causes of obesity, the limitations of some currently trendy policy interventions, and some final thoughts on how this seems to me likely to play out in the long run.

Obesities and Their Causes

First, there is, and long has been, a lot more of pseudo-science or popular science about obesity than real understanding.  One thing should be clear, but seems almost never to be acknowledged:  if viewed through a medical lens, “obesity” is the name for a symptom, not for a single condition with a single cause.  “Hepatitis” is the medical term for inflammation of the liver, derived from the Greek word for liver.  It was a diagnosis, but the term is now used, with appropriate modifiers, for several different kinds of liver problems, with different infectious or environmental causes.  Most researchers now think that what we call “schizophrenia” or “autism” are actually several (if not many) different disorders, with different causes and different possible treatments.  Even cancers of particular organ systems, like lung or breast cancer, are subdividing into more and more types of malignant cells, sometimes being classified based on nothing more than different cell surface receptors on their membranes.  But which receptors a tumor’s cells carry may determine the proper treatment, and the patient’s life or death.

It will be shocking if “obesity” turns out to be one thing, let alone one thing sharing as its only cause in any meaningful way “eating too much.”  Age of onset, location of fat deposits (“apple shapes” versus “pear shapes”), ease of contracting, ease of treating, effects on health – these and many other things will vary among fat people.  Some few will even have a straightforward physiological cause, such as an endocrine disorder, a serious genetic condition whose symptoms include obesity, or even some tumors.  For most people, though, the cause is likely to be some complex combination of genetic predispositions, environmental (mainly diet) triggers, and psychological traits.  Maybe the best way to think about it is that “obesity” will prove to be one health condition the same way “cancer” is one health condition – there will be key defining characteristics in common (too much fat, on the one hand; cells proliferating out of control, on the other), but many different causes, preventive measures, and treatments.

Science journalist Gary Taubes has a nice “World View” column in the December 13, 2012 issue of Nature, entitled  “Treat Obesity as Physiology, Not Physics,” (here).  Taubes has written frequently on obesity, including a book, Why We Get Fat.  I first noticed his writing in this area when he wrote a scathing evisceration of the idea that the percentage of calories in our diet coming from fat had anything to do with obesity, tracing the idea to (literally, and solely) two lawyers working on a Senate committee staff in the 1970s.

Taubes, as his Nature piece sets out, has come to believe that American thinking on obesity has been fixated since the end of World War II on an “energy balance” view of obesity, based on the idea of University of Michigan physician Louis New­burgh, that obese individuals had a “perverted appetite” that failed to match the calories that they consumed with their bodies’ metabolic needs. “All obese persons are alike in one fundamental respect,” Newburgh insisted, “they literally overeat.” This paradigm of energy balance/overeating/gluttony/sloth became the conventional, unquestioned explanation for why we get fat.

Instead, Taubes believes that an earlier European tradition that identified obesity with hormonal dysfunctions was more accurate.  Taubes’s own view is that having a diet high in easily digestible (high glycemic index) and sweet (high fructose) carbohydrates causes higher insulin levels, which in turn causes most obesity, and the current epidemic.  He recognizes that this is a hypothesis, not the proven truth, but, through the Nutrition Science Initiative, which he co-founded, is pushing to have this, and the opposing “energy balance” theory rigorously tested.

I certainly don’t know which, if either, of those two theories is “right” – or “how right” either is – but it is striking how little rigorous evidence we have about why and how people get fat.  Part of that, of course, is because really controlled trials are hard.  People get fat over a long period time and controlling, or even measuring, exactly what they eat and do during that time is very hard.  (Especially since people, much more than mice and rats, cheat and lie when it comes to food.)  Although the energy balance hypothesis has led to simple advice (“eat less, exercise more”), its success in stemming the tide of obesity is, clearly, beyond underwhelming.

Four Policy Interventions

The worries about obesity, in the context of limited evidence about its causes or cures, have led to some proposed interventions that seem, to me, likely to be, at best, useless but harmless and, at worst, largely useless but quite harmful indeed.  I will talk about four such interventions here:  redeeming “food deserts,” restricting junk food, regulating advertising and disclosures, and increasing sanctions on the obese.

Some people seem to think that the problem with obesity, especially in poor and minority communities, is the lack of access to farmers’ markets, Whole Foods Markets, and their equivalents.  “If only the poor could buy reasonably priced kale,” they (don’t quite) say, “obesity would melt away.”  Good luck with that.  I think getting more food choices into poor neighborhoods at reasonable prices would be a good thing (especially that “reasonable prices” part), but I have to believe (without, I’ll admit, any rigorous evidence) that most people – poor or rich – prefer calorie, salt, and sugar stuffed foods to “wholesome” foods because most people enjoy the former more than the latter.  How much is taste, how much is “fullness,” how much is habit is hard to know, but it is more than the lack of easy to buy fresh fruits and vegetables.  (By the way, my wife makes a kale recipe we love – it is sautéed in bacon grease and served with crumbled bacon and white beans.)  The same is true of school lunches.  Put squash in that cafeteria line – even really tasty squash – up against french fries and I think I can predict which one will usually win.   I don’t believe better availability of more “good” food wouldn’t help some people lose weight – just very, very few people.  It won’t dent the obesity problem.

Similarly, restricting junk food (or trying to restrict junk food) seems to me similarly unlikely to have much effect.  Whether it is zoning against fast food restaurants or banning soft drinks of more than 16 ounces, increasing the hassle of getting lots of very high calorie (or very low nutrient) food probably will make some differences.  Some people might eat less; some might eat the same total amount but in less frequent trips (gorging or hording), some might even stop buying chili cheese curly fries at the drive-through and instead buy the ingredients at Safeway and make them at home.  Better for the wallet, not for the waistline.  Again, I am not saying this will make no difference; banning cigarette vending machines probably was a (small) factor in reducing smoking.  I just don’t think it will do much – and its political costs will be substantial.

Regulating information about food is a third approach.  One could try, for example, to ban advertisements for McDonalds on children’s cartoon shows.  Or, as we have done to some extent, one could try to force companies to “speak” through requirements that they disclose nutritional information about their food.  Whether either advertising limitations or disclosure requirements would be very effective seems doubtful. Again, they might cause small changes, but I think only small ones.  Disclosure could help truly motivated dieters, for example, diet more effectively.  But even if these methods were effective, are they feasible?  The politics would be tricky but not necessarily impossible, particularly as companies want to look like they are being responsible (heck, most of them probably even really do want to act responsibly, as long as profits aren’t affected).

But, to mention a third publication I recently read, the Commercial Speech Doctrine might prove a substantial barrier.  Conservative judges and justices have been regularly expanding the free speech rights of businesses to make money without annoying government interference.  (See, for example, an earlier CLB blog post on a Second Circuit case finding that a criminal conviction for illegal off-label promotion of pharmaceuticals violated the First Amendment, here.)  Tamara R. Piety and Samantha Graff, in The New First Amendment and its Implications for Combating Obesity Through Regulation of Advertising, available through SSRN here, focus on possible First Amendment barriers to regulating advertising of “junk food” to children.  They see cause for concern.

A fourth strategy is to increase the sanctions on being fat in order to discourage it more.  Some want fat taxes in health coverage, increasing the costs for health coverage for the overweight (or decreasing it for the not-overweight, which is almost the same thing).  Others think social stigma may be worthwhile, the way that turning smokers into “outdoors only” lepers did (I suspect) help reduce smoking.  There are three problems with this approach.

One is that it would be hard to increase the costs of being fat in much of America.  The employment discrimination, the nasty comments (or the strongly approving comments for any apparent loss of a pound or three), the social (including romantic) barriers – most people who are overweight pay a high price for it, which is why about half the adults in the country will be on a diet at some point in the year. (Of course, some American cultures, particularly some minority cultures, do not have the same stigma on being fat – I’d love to see an anthropologist try to understand those cultural views and their possible oppositional relationship to the dominant culture’s preference for thinness.)

The second is that those diets rarely work because, for most people who are overweight, losing weight, and keeping it off, is somewhere between hard and impossible.  Increasing the price paid for being overweight will lead to some people losing weight and a few keeping substantial weight off for the long term.  But it will mainly make more people miserable as they try, and fail, to diet.

The third problem, of course, is that it makes people miserable.  Pain and suffering as incentives to “better” behavior have a long history and sometimes they make sense.  But that’s only plausible, I think, when the expected benefits substantially outweigh (too many inadvertent puns on this topic) the costs.  Given points one and two, that seems unlikely here.

The Long Run

I see two possible long run scenarios.

In the first, society slowly and gradually adjusts.  It comes to grips with the new environmental reality – nearly unlimited amounts of very attractive but very fattening food – and has its culture change (“changes its culture” seems far too active in this context) to deal with that reality.

In the 1700s England (and particularly London) had an epidemic of gin. For the first time, hard liquor was available to the masses and the masses liked it . . . way too much. Government interventions came and went but over about thirty or forty years, the epidemic receded to an endemic. Maybe the people most vulnerable died out, maybe people less vulnerable learned to be more careful, maybe social sanctions helped.  Alcoholism remained, I’d guess at a higher level than before, but it was not tearing the culture apart.  (One might argue that the pathological alcohol culture that Prohibition introduced into the US took 30 or 40 years post-repeal to moderate.)

Similar, though somewhat quicker processes seem to work with modern drugs of abuse.  Heroin or crack epidemics burn through a place, and then burn out – or, at least, burn down to a smaller, controllable fire instead of a raging inferno.

Smoking is, of course, another possible example.  Mean annual consumption of cigarettes by American adults went from 50 person in 1900, to about 300 in 1920; 1,000 in 1930;   close to 2,000 in 1940; 3,000 in 1950; plateauing around 4,000 between 1960 and 1970, before beginning a slow decline to today’s figure of about 1,200.  But about 20 percent of the adult population still smokes. That percentage has fallen by half in forty years, but it is still over 40 million American adults.  How much of the smoking fall was caused by a realization of the health effects, by higher taxes, by advertising limitations, by bans on smoking in public places, by concerns about secondhand smoke, by cultural shifts, or simply by smokers dying off at a higher rate?  Who knows – but the cigarette epidemic, like the gin epidemic of the 18^th century, is receding, but still doing damage.

Controlling obesity will be harder than controlling smoking.  Food is harder to control than tobacco – one can’t stop cold turkey.  And the second hand effects are less tangible.  The slow “natural” decline of the obesity epidemic would likely be slow indeed

So what’s the other scenario?  Deus ex machina – or, perhaps better, better body weights through science.   I think our greatest hope has to be in understanding the mechanisms that lead to obesity better and then learn to prevent and treat it better.  Puritans might scoff at the idea of tasty low calorie french fries – “they should eat their brussels sprouts and like it!” – but that, or safe and effective appetite suppressing or metabolism increasing pills, or even surgical interventions with fewer and milder side effects are probably the best hope.  Limiting the harm that comes to people from obesity-encouraging eating habits will be hard – changing those eating habits is likely to be much harder. Letting people eat their cake but not pay a weight price for it will not appeal to those who oppose cake (or support will power), but I suspect it will be the only thing that has a good chance of working in less than half a century.

Where is that research going on?  Pharmaceutical companies have had very limited success with weight loss remedies; research continues but investment is not high.  Food companies have had some successes with lower calorie foods in some contexts; I don’t know what their investment is like.  There is no National Institute of Weight and no American Obesity Association to promote basic scientific research.  Federal research is surely being done – the NIH claims to spend over $800 million a year on research “to reduce the prevalence of obesity and its health consequences.”  How much of that includes say, research on diseases associated with obesity, like diabetes or stroke, is not clear.  But if this is really an important policy problem, spending even the claimed not quite 3 percent of the NIH budget on it seems too little.

This blog post has now gone on about the length of a scientific article, so it is only right that it end with the stereotypical last words of scientific articles:  “further research is required.”

Hank Greely