The Wall Street Journal had a nice forum on whether and to what extent the goverment should "combat" obesity from three experts with different perspectives. I come down on the issue somewhere between Tanner and Wansink.
Blog
Obesity Hype
The Robert Wood Johnson Foundation and Trust for America's Health just released a report entitled F as in Fat: How Obesity Threatens America's Future 2012. The associated press release reports:
For the first time, the annual report includes an analysis that forecasts 2030 adult obesity rates in each state and the likely resulting rise in obesity-related disease rates and health care costs.
and
If obesity rates continue on their current trajectories, by 2030, 13 states could have adult obesity rates above 60 percent, 39 states could have rates above 50 percent, and all 50 states could have rates above 44 percent.
Obesity is out of control! Or is it? If we look at the actual data, we can see that no such explosion in obesity rates are occurring. One group of researchers writing in 2010 in the Journal of the American Medical Association reported that that the prevalence of obesity :
may have entered another period of relative stability.
Another re-appraisal in 2012 by the same authors using new data in the Journal of the American Medical Association reported
Over the 12-year period from 1999 through 2010, obesity showed no significant increase among women overall
and only slight increases for men.
Here is the key graph from the JAMA paper:
As you can see, trends in BMI since 1990-2000 are basically flat.
So, how is it that the Robert Wood Johnson Foundation and Trust for America's Health can claim run-away trends? I don't know, but it makes me suspicious of anything else they claim in their report not to mention their policy prescriptions.
Indeed, it might have done the authors of the report some good to read or at least acknowledge what was written in the 2012 JAMA paper (footnotes omitted):
In part because we know relatively little about the precise causes of the trends previously observed, it is hard to predict the future trends in obesity. Several analyses have modeled increasing obesity prevalence as a function of calendar time and then projected future obesity prevalence from these models. These obesity predictions in effect assume that the causal factors for obesity will continue to rise with time or will have an increasing effect over time, and therefore calendar time itself is a reasonable predictor of future obesity prevalence. However, the results reported here and the apparent slowing of trends suggest these may not be valid assumptions and these predictions may be inaccurate.
Food Police Alert
In an opinion piece in the Journal of the American Medical Association, Thomas Farley praises New York City policies and calls for ramped up regulation to fight obesity:
New York City supported a 1-cent-per-ounce excise tax on sugary drinks to lessen the industry's financial incentive to market large portion sizes and to encourage consumers to choose smaller portions and switch to low-calorie beverages. The city also supported a change in policy on the Supplemental Nutrition Assistance Program that would have prohibited the use of program benefits to purchase sugary drinks, arguing that government should not subsidize the purchase of a product known to be particularly unhealthful. In addition, the city's health department proposed a cap on the portion size of sugary drinks served at restaurants.
He doesn't justify the regulations by showing that they worked or by demonstrating that the benefits are greater than the costs. Rather, his key argument is that the government already regulates many areas of your life:
. . . tens of thousands of restaurant inspections are conducted each year, enforcing rules such as those mandating the temperature at which food can be stored, all to prevent foodborne infectious diseases. The federal government mandates safety features, such as seat belts, in automobiles. Governments at all levels prohibit the use of lead in paint.
The reason you should acquiesce to new government rules is apparently that you've already acquiesced to other government rules.
In the end, the argument amounts to little more than paternalism. People aren't presumed to know what is best for them so let the "experts" decide. It is telling that in the piece, Farley writes:
The sale of huge portions is driven by the food industry, not by consumer demand.
I don't recall the food industry ever forcing me to supersize my Big Mac.
Food Police Alert
New York City's Board of Health approved Bloomberg's ban on large sodas. Here is Scott Shackford at Reason:
The number of exceptions to the ban makes the whole practice an absurd spectacle of pointless progressive authoritarian paternalism. Fruit juices and milkshakes are not affected by the ban even though both can have sugar content right up there with your Cokes and your Mountain Dews. The ban affects restaurants and movie theaters but not convenience stores, so New Yorkers won’t be able to get a 20-ounce soda at McDonald’s, but theywill be able to get a 50-ounce Double Gulp from 7-Eleven. Furthermore, the ban shouldn’t affect diet or sugar-free drinks, but as The New York Timesreports, establishments with self-service fountains will not be able to stock cups that hold more than 16 ounces. So essentially, thirsty people will want to avoid the targeted businesses altogether even if they’re drinking healthy.
One annoying outcome of this half-assed Nanny Statism is how it’s easy it’s going to be to spin an argument for an expansion of the ban regardless of the outcome. If the city’s obesity numbers drop, it will be an argument that the ban worked and it should be expanded. If the obesity numbers don’t drop, it means the ban obviously didn’t go far enough and should be expanded. The drug war’s arguments are on their way to the soda dispenser.
The Science of Sugar
Three years ago, this YouTube video of a talk by Dr. Robert Lustig, a Professor of Pediatric Endocrinology at UC San Francisco, when viral (to date, the video has 2.7 million downloads). His argument there, and subsequently in prestigious journals like Nature, is that sugar is toxic.
I’m going to be honest, I haven’t invested the time to adequately evaluate the claims made about the biology, endocrinology, and metabology of sugar, but I suspect there is some truth to the argument that some foods are metabolized differently than others – in other words, it is more complicated than just “calories in, calories out” (although this adage is also almost certainly true on some level).
What I do know is that the science of sugar is not nearly as certain as Lustig purports, a fact mentioned by Gary Taubes who is overall sympathetic to his claim (see also the citations in second paragraph of Lustig’s Wikipedia page).
Lustig is an accomplished and well-published scientist. But, what bothers me is the all too common stance of many folks in the medical and public health communities failing to appreciate how little they know when they move to realms beyond their particular academic expertise.
The viral YouTube talk included a beginning slide with the words “Letting Science be the Guide” and Lustig personally began a speech in 2011 by asserting that “Ultimately science should drive policy.” Yet, I find it a bit ironic that neither of these talks seriously discusses the economic science behind the many sugar-recuing policies he supports.
Economic study after study after study after study shows sugar policies (such as sweetened beverage taxes or bans on school vending machines) will only have very small effects on intake and weight. When sodas are taxed (or banned), people can substitute toward other caloric drinks such as fruit juice or alcohol. Moreover, food taxes are regressive - meaning the burden is disproportionately borne by the poor. It is also worth pointing to the economic research on farm policy and sugar production reveals a much more complicated situation than many pundits presume, with the authors showing that the “link between US sweetener consumption and farm policy is weak.”
So the next time you hear someone pronounce that the “government has to get off its ass” because of sugar consumption, I suggest asking what economic science actually says about what will happen when the government moves it’s preverbal backside.
Addendum: One of my colleagues pointed out that the arguments used to claim sugar is addictive (primarily that our body becomes accustomed to a level of intake and requires more and more to achieve a given level of satisfaction) sounds remarkably like the psychologist’s notion of the hedonic treadmill – a phenomenon that is posited to hold for almost all aspects of life.