Science of Obesity

Last week the journal BMJ (formerly the British Medical Journal) published an essay by Gary Taubes.  His article contained a lot of good sense about the state knowledge on the science of obesity and reveals how little we really know.  

Here is a key excerpt:​

Another problem endemic to obesity and nutrition research since the second world war has been the assumption that poorly controlled experiments and observational studies are sufficient basis on which to form beliefs and promulgate public health guidelines. This is rationalised by the fact that it’s exceedingly difficult (and inordinately expensive) to do better science when dealing with humans and long term chronic diseases. This may be true, but it doesn’t negate the fact the evidence generated from this research is inherently incapable of establishing reliable knowledge.

and

Without rigorous experimental tests, we know nothing meaningful about the cause of the disease states we’re studying or about the therapies that might work to ameliorate them. All we have are speculations.

As for the experimental trials, these too have been flawed.

and

Rather than acknowledge that these trials are incapable of answering the question of what causes obesity (assumed to be obvious, in any case), this research is still treated as relevant, at least, to the question of what diet works best to resolve it—and that in turn as relevant to the causality question.

and in conclusion

We believe that ultimately three conditions are necessary to make progress in the struggle against obesity and its related chronic diseases—type 2 diabetes, most notably. First is the acceptance of the existence of an alternative hypothesis of obesity, or even multiple alternative hypotheses, with the understanding that these, too, adhere to the laws of physics and must be tested rigorously.

Second is a refusal to accept substandard science as sufficient to establish reliable knowledge, let alone for public health guidelines. When the results of studies are published, the authors must be brutally honest about the possible shortcomings and all reasonable alternative explanations for what they observed.

Organic Shampoo Over-Rated Too?

​I'm not a big follower of developments in beauty products.  But my wife is (not that she needs it!).  In any event, she passed along this interesting exchange on a cosmetic web site.  I wonder if the hair expert will receive the same kind of attacks as my recent Huffington Post article that challenged some of the conventional wisdom of organic food.

Dear Paula,
I have an itchy scalp. I also have color-treated hair, so my hair can feel dry. I used Aveda Brilliant Shampoo for many years. I loved the way it gave fullness to my hair but then I learned it was not wholly organic so stopped using it. . . . I like organic stuff and have tried olive oil, rosemary oil, and vinegar for itchy scalp, but am frustrated and just don't know what to look for anymore. Help!

Jan

Dear Jan,

First, you need to let go of the idea that natural and organic products are better for your hair and scalp. Although I understand the pull organic products have, the truth is such products typically contain ingredients that are likely what caused some of the problems you’re dealing with now, especially the itchy scalp. 

A great shampoo should be a blend of synthetic and natural ingredients, but even then the natural ingredients often do little other than look good on the label. Natural ingredients cannot do a very good job of cleansing the scalp or removing styling product buildup from hair—one reason shampoos with mostly natural ingredients tend to leave hair feeling worse, not better. . . 

Reasons to Rethink Organic

The Huffington Post put up a slide show with some excerpts from the chapter on organic foods in The Food Police.  Here is the lead in:

Everywhere you turn, you hear "organic is healthier", "organic is greener", or "you absolutely MUST buy organic." It's not a question of whether we want to eat healthy, environmentally friendly food -- who doesn't want that? The question is whether organic lives up to the hype and whether it's worth it to pay a hefty premium. One of the problems with organic is that few shoppers know what the term really means, and they project onto the nebulous word all their hopes and dreams of good eating. Despite what many believe, organic doesn't mean food from small farms, produced without pesticides, or grown in the USA. There are a few advantages to eating organic but there are some drawbacks too. If you're rich enough and well-informed on the issues, then I say go for it. But, if you're not so sure whether organic lives up to all it is promised to be, here are a few reasons to re-think doubling your grocery bill.

Solving Obesity Externalities

​It doesn't matter whether you listen to Bill Maher on the left or Sean Hannity on the right,  you'll hear guests on their show arguing that something should be done about obesity because one's weight imposes a cost on others.  Obesity, they argue, is an externality, and therefore requires government regulation to make private costs equal social costs. 

Many of these argument surround the health care expenses incurred by Medicare and Medicaid.  I don't think that is a particularly good argument, but I don't want to get into that in this post.  Rather, I want to remind readers of what the Nobel prize winner, Ronald Coase, taught us regarding externalities.  ​In particular, if your behavior is harming me, I now have an incentive to negotiate with you to lessen the harm done.  

​It appears that at least one airline, has taken this lesson to heart.  According to the CNN story:

The head of Samoa Air has defended its policy of charging passengers by their weight, arguing such a system is not only fair but the future for other airlines.

and:​

What makes airplanes work is weight. We are not selling seats, we are selling weight.

and:

According to the airline's website, "your weight plus your baggage items is what you pay for. Simple."

​

I suspect there will be quite a few folks who don't like this policy.  Yet, we already have to pay airlines if we want to check bags or sit in the seats with more leg room.  You're free to bring several bags or stretch out your legs, but the airline is going to make you pay for that privilege rather than charging it to all passengers.  

But, surely this isn't fair because (some) people can't affect their weight.  Yes, but I also can't affect my gender, my height, my age, or my race - all of which have been shown in various studies to affect wages, employment outcomes, and so on.  Men pay more for life insurance than women because we're riskier.  It is hard for me to see that it would be "fair" to force women to pay more for life insurance (to partially pick up men's cost) simply because men are likely to die sooner for some reasons under their control and some that aren't.       

It is almost certainly true that heavier passengers cost the airline more money (and thus raise the prices of airline tickets for everyone else).  ​Ultimately, the airline isn't discriminating against over-weight people, they're simply applying equality to every pound that enters their plane.  To do otherwise is to ask the thin to pay more than their "fair share."  

How is it that I can support an airline trying to solve an obesity-externality problem when I'm skeptical of the government ​doing the same?  Competition.  If you don't like Samoa Air's policy, don't fly their airline.  Moreover, if their policy turns out to be one that people (thick and think alike) don't like, there will ultimately be another airline that enters the marketplace to offer passengers a more desirable deal.  Samoa Air may ultimately find that trying to regulate their obesity externalities simply isn't worth the effort, and if that is indeed the case, I suspect you'll see a rapid reversal of policy after a few poor quarterly earnings reports.

Is Organic Sustainable?

I ​ran across this really interesting blog (via Tyler Cowen's blog) post on nitrogen use in agriculture by Adam Merberg, who says he is a "reformed food reformer."  

Merberg's main point is that, aside from a small handful of crops, nitrogen is a key limiting ingredient in growing more food.  ​Much of the nitrogen used in modern commercial agriculture comes from the air!  Well, it's taken out of the air by a "synthetic" process that prohibits its use in organic agriculture.

Organic agriculture, like all agriculture, requires nitrogen.  Soil (regardless of how you farm) looses fertility after a while and requires replenishment to continue productivity.  Organic seeks nitrogen in cover crops (like clover and soy) but mainly through use animal manure.  Merberg asks a reasonable question: where does the manure get it's nitrogen.  The answer is that it largely comes through conventional agriculture and the "synthetic" process invented by Haber.  The manure spread on many organic farms comes from cows/hogs/chickens that ate grains grown using "synthetic" fertilizer.  

When we read that organic can "feed the world" we need to ask where all the nitrogen will come from to make it happen.  ​

Here are a few snippets from Merber's article (the back-and-forth in the comments was interesting too):​

By identifying manure as a source of nitrogen, Vasilikiotis dodges the issue of nitrogen fixation entirely. However much nitrogen exists in manure today, much of it has been fixed industrially before being taken up by corn plants and laundered through the guts of conventionally-farmed animals. Vasilikiotis does not explain how that manure might come to be in an organic world. To do so would require demonstrating the potential for sufficient biological nitrogen fixation

​and

Natural processes, like atmospheric nitrogen deposition, can help replenish some nutrients, but the fact remains that the nutrient cycle remains open. Maintaining modern yields generally requires inputs of some kind to replace nutrients removed in crops. For instance, Joel Salatin’s Polyface Farm–which Pollan’s The Omnivore’s Dilemma identifies as a model for sustainable agriculture and describes as “completely self-sufficient in nitrogen”–actually brings in nitrogen in conventionally-grown grain, which is fed to chickens whose manure fertilizes the pasture.

and, interestingly . . .​

In recent years, the US government has begun allowing the recycling of human waste by authorizing the use of treated sewage sludge, called biosolids, as fertilizers. However, in 1998 organic advocates successfully protested proposed guidelines which would have allowed application of biosolids in organic agriculture. Whatever the merits of their objections, it is ironic that the movement for a more “natural” agriculture now opposes ending the waste of nutrients that Liebig once decried as “a sinful violation of the divine laws of Nature.”

​

For the record, I'm not against organics.  But, I am against the mis-truths that are often spread in their defense.  ​