Nutritional Guidelines Redux

By now, I'm sure many readers have seen the announcement that the secretaries of the USDA and HHS have announced that the latest dietary guidelines will NOT include issues of sustainability.

This is a topic I've commented on several times in the past, and I was interviewed by Stewart Varney on the Fox Business Network yesterday about the development (I haven't found a link yet to post).

Here are just a few scattered thoughts and comments.

First, it is a bit odd that the nutritional guidelines don't consider behavioral responses of consumers.  That is, if it is recommended not to eat food type X, then what will consumers switch to eating instead?  Note that the question isn't: what do we wish consumers would eat instead, but rather what substitutions will actually occur?  This issue was highlighted in a post by Aaron Carroll on the NYT Upshot blog when discussing a large study that showed reducing saturated fat intake didn't produce noticeable health benefits: 

The study also resulted in a reduction of unsaturated fats and an increase in carbs. That’s specifically what the committee argues shouldn’t happen. It says that bad fats should be replaced with better fats. However, people did reduce their saturated fats to 10 percent of intake, and didn’t see real improvements in outcomes. This has led many to question whether the quantitative recommendation made by the committee is supported by research.

In a day and age when behavioral economics is all the rage, and is even being required by the White House, it is a bit absurd to believe consumers will follow all the guidelines and recommendations to-a-tee.  A more pragmatic approach is to realize most people will devote enough attention to get a couple take-home messages, and then act.  We need to study how consumers will actually substitute given their preferences and the messages they digest.  This isn't necessarily a critique of information behind the guidelines themselves (after all, we do want some systematic, scientific summary of the state of nutritional knowledge), but rather a call for research on how the guidelines are actually implemented and communicated and are ultimately used by consumers.

Second, this article by Tania Lombrozo at NPR touches on an issue I addressed several months ago: when guidelines mix nutrition and "sustainability", it necessarily involves value judgments not  science.  She writes:

Science can (and should) inform our decisions, but you can’t read off policy from science. Invoking science as an arbiter for questions of values isn’t just misguided, it’s dangerous — it fails to recognize what science can (and can’t) provide and it fails to make room for the conversations we should be having: conversations about the kinds of lives we ought to live, the obligations we have to each other, to future humans and to other animals, and — among other things — what that means for the food choices we make every day.

Finally, looking at a lot of discussion surrounding this issue, while the guidelines purportedly discuss "sustainability" - the issue is often boiled down to a single issue: greenhouse gas emissions.  While it is clear that beef is a larger emitter of greenhouse gasses than most other animal and plant-based food, the impacts need to be placed in context.  In the US, livestock production probably accounts for a very small percentage of all all greenhouse gas emissions.  Telling people to eat less meat will likely have small effects on greenhouse gas emissions.  My gut feeling is that further investments in productivity-enhancing research will have a larger effect on greenhouse gas emissions than cajoling consumers.  

In other places discussing "sustainability" the issue of food security is mentioned, as is resource use.  To an economist's ears, when I hear "resource use", I immediately think of prices.  Prices are the mechanism by which resources get efficiently allocated in a market-based economy.  As such, it gives me pause when I think of a report by a a group of nutritionists making recommendations on proper resource use.   I'd never trust a dictator (or even a group of economists) on having enough knowledge to making optimal decisions on resource use.  Beef is a relatively expensive food.  That tells us it is using a lot of resources, and that higher price causes us to eat less than we otherwise would.  

But, what about externalities?  To the extent beef production uses a lot of corn or land, that's already reflected in the price of beef.  But, does the price of beef reflect water use and potential (long run) impacts of greenhouse has emissions?  Probably not fully.  So, the key there is to try to get the prices right.  Well functioning water markets would be a start.  Greg Mankiw recently had an interview on getting the price of carbon right.  Once the prices are right, then "recommendations" regarding resource use are somewhat meaningless: you're either willing to pay (and able) the price to buy the items you like to eat or not.