Does a Good Diet Guarantee Good Health?

To be sure, dietary factors contribute to bad health at least some of the time for some people.  But, how large a role does diet play?  Stated differently: even if you eat well all the time, are you guaranteed to be free of cancer, heart disease, and diabetes?  Far from it according to two recent studies.  

The first was published Friday in Science by Tomasetti, Li, and Vogelstein, who investigated cancer causes.  When discussing the things that can cause cancer, causes normally fall into one of two broad categories: nature (environmental factors) or nurture (inherited genetic factors).  These authors, however, point to a third factor: as we grow, our cells naturally replicate themselves, and in the process, unavoidable DNA replication errors occur which ultimately lead to cancer.  The authors calculate that these replication errors or  

mutations are responsible for two-thirds of the mutations in human cancers.

Secondly, I ran across this interesting paper published a couple weeks ago in the Journal of the American Medical Association.  The authors attempted to ferret out how many deaths from heart disease, stroke, and type 2 diabetes (what the authors call "cardiometabolic deaths") that result each year annually come about from over- or under-consumption of certain types of foods.  As this critic pointed out, it is important to note that the authors estimates are associations/correlations NOT causation.  As such, I'd suggest caution in placing too much interpretation on the impacts from different types of food.  Nonetheless, there were a couple of other less-well-publicized results which I found interesting.

First, the authors found:

In 2012, suboptimal intake of dietary factors was associated with an estimated 318 656 cardiometabolic deaths, representing 45.4% of cardiometabolic deaths.

Stated differently, 54.6% of deaths from heart disease, stroke, and type 2 diabetes seems to be caused by something other than diet.   

The other result that I found interesting from this study is that there has been a big decline in so-called cardiometabolic deaths.  The authors write:

Between 2002 and 2012, population-adjusted US cardiometabolic deaths per year decreased by 26.5%.

Some of this decline, they argue, is due to reduced sugar consumption and increased nut/seed consumption from 2002 to 2012.

Why does all this matter?  Because these statistics help us understand the impacts of dietary and lifestyle changes.  To illustrate, let's take the above cancer statistic: 66.7% of cancers are caused by unavoidable replication errors. That leaves 33.3% of cancers, some of which are diet and lifestyle related and some of which are caused by inherited genetic factors.  For sake of simplicity, lets say you have zero risk from inherited genetic factors. Also note that the National Cancer Institute suggests that the chances of getting a new cancer in a given year are 454.8 per 100,000 people (or a 0.45% chance).  

Putting it all together, your chance of getting cancer from random errors in DNA replication is 0.667*0.45%=0.30%, and your chance of getting cancer from diet and lifestyle factors (assuming no inherited risks) is 0.333*0.45%=0.15%.  So, even if you could completely eliminate the cancer risk from diet and lifestyle factors, you'd go from a 0.45% chance of getting a new cancer to a 0.30% chance, a reduction of 0.15 percentage points.

The Problem of Food Waste Over-stated?

Marc Bellemare and colleagues at the University of Minnesota have an important new paper out on food waste.

First, they note that there are important weaknesses and inconsistencies in the leading definitions of food waste published by the United Nations, the USDA, and the European Union.  Second, they provide compelling conceptual reasons to suggest that reported measures of food waste are almost certainly overstated.  Finally, they propose a conceptual logically-consistent approach to measure food waste.  

The arguments for why the value of food waste is overstated boil down to two factors: 1) some "waste" has productive uses as animal feed, compost, etc. and 2) the value of wasted food is often "priced" at the retail level, when in fact the actual waste occurs further upstream the supply chain where commodity prices are lower.  

You can read the whole paper here.


I am pleased to announce that I have officially accepted an offer to be the next Head of the Department of Agricultural Economics at Purdue University (I will also be nominated for the post of Distinguished Professor at Purdue) and will begin there after the first of July.

I have thoroughly enjoyed my 12 years at Oklahoma State and appreciate the support and opportunities OSU has afforded me. I've had great students and colleagues, and have made wonderful friends in Stillwater.  But, now’s the time to move on to a new challenge.  

The college of agriculture at Purdue is routinely ranked in the top 5 to 10 worldwide, and the Department of Agricultural Economics has a long history of excellence and leadership in the profession.  It's a large department with about 50 faculty members, almost 150 graduate students, and 600 undergraduates.  It's a big job and I'm looking forward to it.  

What kind of farmer are you?

A couple days ago, I reported the results from the Food Demand Survey (FooDS) for March 2017. In addition to a typical question we ask every month "Have you ever worked on a farm or ranch?", we added a new follow up question, "Which of the following best describes the kind of farm you worked on? (Check all that apply)."

As I reported then, about 17% of people said yes to the first question.  Of this 17%, about 38% followed it up by saying the type of farm was a "garden in your backyard", 23% said "A chicken coop in your backyard" and 12% said "a community garden".  I received some Twitter questions and reaction to the results.  

Here's one vein of reaction:

Of course, this is exactly what we wanted to know: who are the people checking "yes" to this question and what do they (not us) consider farm or ranch work? 

A more substantive question was this one:

The answer is "yes".  This was a "check all that apply" question and a lot of commodity crop and livestock farms also have backyard gardens and chickens.  To get at this issue more directly, I went back to the data and looked at the 17% who said "yes" they had worked on a farm and ranch and looked at the percent of respondents who said they had a backyard garden (or chicken coop or community garden) but did NOT check “A farm that produces commodity crops (e.g. corn, wheat, soybeans, cotton, or rice)” or “A farm that produces commercial livestock (e.g. cattle, swine, or poultry).” 

Here are the results: of the 17% who said they'd worked on a farm or ranch: 4.7% indicated working in a community garden but NOT a commodity crop or livestock operation, 12.2% indicated they worked in a garden in their backyard but NOT in commodity crop or livestock operation, and 7.5% said they had a chicken coop in their backyard but had NOT worked in a commodity crop or livestock operation.  

Food Demand Survey (FooDS) - March 2017

The March 2017 edition of the Food Demand Survey (FooDS) is now out.

Some items from the regular tracking portion of the survey:

  • Willingness-to-pay (WTP) decreased for steak, pork chops, and especially deli ham. WTP increased for chicken breast, hamburger, and chicken wings. WTPs for all meat products are lower than one year ago, except for hamburger.
  • Consumers expect higher beef, chicken, and pork prices compared to one month ago. Consumers plan to buy slightly less chicken and beef compared to last month.
  • The largest percentage increase in concern was for bird flu and the largest decrease in concern was for farm animal welfare.

Several new ad hoc questions were added to this month’s survey that mainly dealt with knowledge of farm production practices.

Participants were first asked: “Have you ever worked on a farm or ranch?”. About 17% of participants answered “yes.” Participants who answered “yes” were then asked “which of the following best describes the kind of farm you worked on?” Respondents were provided with six options and they could check all that applied.

Of the 17% who said they had worked on a farm, 43% checked “A farm that produces commodity crops (e.g. corn, wheat, soybeans, cotton, or rice)” followed by 40% who checked “A farm that produces commercial livestock (e.g. cattle, swine, or poultry).” “A garden in your backyard” was picked by 38% and “A chicken coop in your backyard” was picked by 23%. 20% checked “other” (and provided responses such as working on a dairy farm or a horse farm or on school farms such as FFA), and 12% checked “A community garden”.

Secondly, participants were asked: "Which of the following animal production industries use added growth hormones?” Over half of participants stated that believed beef, pork, poultry and dairy industries use added growth hormones. Over 75% of participants indicated that they thought that the beef cattle industry uses added growth hormones. Over half of the respondents stated they believe the swine and poultry industries to uses added growth hormones. In reality, the swine and poultry industries do not use any added growth hormones. About 57% of participants stated they believed added growth hormones are used in the dairy industry.

Third, participants were asked: “What percentage of dairy cattle in the U.S. are treated with rBGH?” Overall participants perceive a much greater use of rBGH in dairy cattle than what is actually used. About 20% of participants believe that 50-59% of dairy cattle are treated with rBGH. 5.7% believe that 90- 100% of dairy cattle are treated with rBGH. Only, 10.9% of participants stated that less than 10% of dairy cattle are treated with rBGH. In reality, less than ten percent of all dairy cattle in the U.S. are treated with rBGH.

Lastly, participants were asked: “To what extent do you agree or disagree with the following statements?” Individuals responded on a 5-point scale: 1=strongly disagree, 2=somewhat disagree, 3=neither agree nor disagree, 4=somewhat agree, 5=strongly agree.

The most common answer for each item was “neither agree nor disagree”, except for the statement all milk contains natural hormones where the most common answer was “somewhat agree”. The statement “all cow’s milk contains natural hormones” was agreed upon most, whereas the statement “hormones are never given to dairy cattle” was agreed upon least.
About 38% of participants answered “somewhat agree” or “strongly agree” that it is healthier to consume milk labeled rBGH free. Approximately 30% of participants answered “somewhat agree or “strongly agree” that conventionally produced milk contains unsafe levels of hormones. Only 5.6% of participants selected “strongly disagree” that milk containing rBGH tastes different.