Hunter Gatherer

Brimming with ideas and a fascinating read. STEVEN PINKER, Johnstone Professor of Psychology, Harvard University

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Media hysteria on tanning beds and melanoma

A recent study on tanning beds and melanoma has been making the rounds: "Indoor Tanning and Risk of Melanoma: A Case-Control Study in a Highly Exposed Population".  The WSJ, TimeNPR, and USA Today have all covered it.  The big statistic that everyone is throwing around is that "people who tanned indoors had a 74% higher chance of developing melanoma than those who hadn’t."  Note that the reason this paper is such a big deal is because there has never been strong evidence that using tanning beds caused melanoma.

Well, I had the great pleasure of meeting Dr. Michael Holick today, and we discussed this very paper.  You can view the full text here.  Let’s go the actual science and see what it says.

The 74% number comes from Table 3, second row, in the last column called multivariate adjusted OR (odds ratio).  You’ll see a 1.74 (hence, 74% more likely), plus a confidence interval.  (This interval, or error bounds, simply indicates that if you ran this experiment 100 times, 95% of the time you’d expect this value to fall between 1.42 and 2.14.)  The odds ratio for hours spent in a tanning bed increases to 3.18 (218% more likely) with duration of tanning bed use.

Well, from all the media hysteria, you’d expect that tanning beds would be the primary risk factor uncovered in the study.  And you’d be wrong.  Flip up to Table 2 and let’s take a look at the odds ratios of other factors.

Hair Color

What color is your hair?  Redheads have an OR of 3.53 — which means red heads are 253% more likely to get melanoma.  Compare that to the 74% number associated with ever having gone to the tanning salon.  And even blondes are 117% more likely (2.17 OR).  Having blonde hair or red hair has more to do with your risk of melanoma than whether you’ve ever gone to the tanning salon.  

Skin Color

Having very fair skin increases your chances of melanoma by a whopping 450% (5.50 OR).  Fair skin is 263% more likely, and even light olive skin is more important than having gone to the tanning salon.


Moles!!!  If you have a bunch of moles you’re 1,281% more likely to get melanoma.  Having lots of moles is nearly 20X more important than whether you’ve gone to a tanning salon.

Lifetime Sun Exposure

Three measure of sun exposure show that high lifetime sun exposure decreases risk of melanoma (ORs of .85, .95, and .84).

Sun Burns

Sun burns, on the other hand, do increase your risk of melanoma, comparable to tanning salon usage.  

Mean Lifetime Sunscreen Use

Get this — THE SAME STUDY THAT CONNECTS TANNING BEDS WITH MELANOMA ALSO CONCLUDES THAT HIGHER SUNSCREEN USAGE INCREASES YOUR RISK OF MELANOMA.  Medium or High mean lifetime sunscreen usage increases your chances of getting melanoma by about 30%.  But somehow "Sunscreen usage causes melanoma" is a less catchy headline than "Tanning beds cause melanoma".

My point is not that there are no risks to tanning beds.  My point is that the biggest risk factors for melanoma are NOT tanning bed usage and are NOT sun exposure.  It’s having moles.  And red hair or blonde hair.  And fair skin.

So how about we do some science that actually tries to understand what’s going on, instead of attention-grabbing headlines that confuse and scare people. 


I’m on a bus on my way up to Cambridge, Massachusetts for my 5th year college reunion.  So what better time than now to bore you with reflections on my past five years and with my answer to the age-old question: "If you could do it all over again, what would you do differently?"

If I could change one thing about my college experience, I would have been healthier.  Number one.  Better food, less drinking, more sleep, more sun, more exercise.  Did I mention less drinking?

I’m sure my four years were a lot like others’ when it came to food.  French fries, pizza, and Dr. Pepper were the foundation of my food pyramid.  The cafeteria did have a few healthy options, and I would often make a little side salad.  But most people have this wierd notion that eating healthy is additive — that if you add a few healthy items to your meal, like vegetables, you’re eating healthy.  For most of us though, the first step to eating healthy is subtractive — avoiding a lot of the worst foods out there.  And four years of all-you-can-eat is a bit more conducive to the additive approach to nutrition than the subtractive one.

I drank a lot too.  I mean, not particularly more than any other extroverted guys at school (okay, maybe a little more), and Harvard isn’t exactly known for prowess in drinking (though saying that might be a calculated decision to get you to underestimate us in a drinking competition, a dangerous mistake). But I remember losing ENTIRE DAYS to hangovers.  Big night out, to bed in the wee hours, and not being able to crawl out of bed (except to the bathroom) until dinner the next day.  And this was normal.

For me, being healthier wouldn’t have been about weight.  I didn’t gain much weight, if any, during college.  First and foremost, it would have been about mood and outlook.  My mood and energy was up and down, up and down.  My senior year, one of my good friends once called me "The happiest sad guy he knew."  What the hell type of commentary is that?  My mental state has improved to where I have difficulty remembering the types of negative thoughts that can enter a college student’s head.  More on that later.

The second area would have been complexion — my complexion is drastically improved and I rarely, if ever, get pimples or zits anymore.  This is a big deal.

And third, I would have been able to get more done.  See: "Hangovers, 12-hour".

Anyhow, it will be interesting to see how people turned out.  There’s always a few that put on 25 pounds and look like they’re 40 years old.  Who are the unlucky ones?

(Also, something to look forward to — I’m dropping by Dan Lieberman’s lab, where they’ve done all the cool work on barefoot running.  The bad news is that they’re busy doing experiments and so can’t do any gait analysis.  The good news is that they’re running experiments on RAW MEAT!)

John Durant

The origins of corn

Corn, or maize, now accounts for over 20% human caloric intake.  But the exact origins of corn were in doubt until recently.  Early genetic experiments (before genetic testing) pointed to teosinte.  And newer genetic experiments (proper sequencing) suggest that teosinte was domesticated starting about 9,000 years ago:

"In order to trace maize’s paternity, botanists led by my colleague John Doebley of the University of Wisconsin rounded up more than 60 samples of teosinte from across its entire geographic range in the Western Hemisphere and compared their DNA profile with all varieties of maize. They discovered that all maize was genetically most similar to a teosinte type from the tropical Central Balsas River Valley of southern Mexico, suggesting that this region was the “cradle” of maize evolution. Furthermore, by calculating the genetic distance between modern maize and Balsas teosinte, they estimated that domestication occurred about 9,000 years ago."

And it was probably a slow process:

"It is estimated that the initial domestication process that produced the basic maize form required at least several hundred to perhaps a few thousand years."

Read the full New York Times article here.

Tips for travelers: the hard-boiled egg

I find myself in airports a lot.

And in some ways, airport food is worse than airplane food.  At least airplane food is so bad that it’s not even tempting.  (If they even serve it anymore.)  But when you find yourself in an airport, there are lots of unhealthy food options — and you’re typically stressed out and in a rush.

The best food options usually are:

  • a nearly frozen chef salad loaded with cheddar cheese
  • over- or under-ripe fruit (often apples that leave your teeth sticky with sugar residue)
  • a small, $8 bag of nuts (where they try to tempt you to buy a sugar-loaded candy / dried fruit / peanut mix)
  • use the opportunity to fast (a la Art De Vany)

Well, there is a welcome development!  Enter the hard-boiled egg.  I’ve recently noticed that a number of cafes, coffee shops, and even 7-11 now carry a little package with a pair of hard-boiled eggs.  This is a great way to get some convenient, real food on the go.  Cheap too.

And remember, eggs are good for you, including the yolk!

A small conceit

I snapped a screenshot of my Colbert interview as the view count passed Pollan’s.  I’m coming for you, Pollan.


NBA players moving away from hightops

The athletic shoe is having a rough few years.  From best-selling Born to Run, Harvard professor Dan Lieberman’s work on barefoot running in Nature, to the success of Vibram Five Fingers.  And now, the NBA: players are moving away from hightops that allegedly provide more ankle support.

"One of the reasons hightops are going out of vogue, players and injury experts say, is that there’s some research that suggests they aren’t very good at protecting your feet. NBA players missed 64% more games last season because of foot-related injuries than they did twenty years ago, according to NBA statistician Harvey Pollack."

There are multiple reasons why foot injuries could be going up:

"Players have gotten taller and heavier, the pace of the game is faster and the NBA postseason has gotten longer."

But for a piece of conventional athletic wisdom, "ankle support" has surprising little support.

"Craig Richards, a researcher at Australia’s University of Newcastle, published a 2008 article in the British Journal of Sports Medicine that catalogued academic studies in athletics and found no evidence that sneakers limited injuries. His research actually found that hightop basketball sneakers make players run slower and jump lower."


(Thanks to Cheryl for the pointer.)

Assorted links


 1. Another benchmark in Craig Venter’s quest to create life.
The pros: "I think they’re going to potentially create a new industrial revolution," [Venter] said.  "If we can really get cells to do the production that we want, they could help wean us off oil and reverse some of the damage to the environment by capturing carbon dioxide."
The cons: "We don’t know how these organisms will behave in the environment." [Dr. Helen Wallace of Genewatch]
2. Michael Holick interview with the New York Times (a few months old)
"The American Academy of Dermatology still has that recommendation that you should never be exposed to one ray of direct sunlight without sun protection."
3. Michael Pollan’s The Food Movement, Rising in the New York Review of Books
On the different parts of the food movement:
"Among the many threads of advocacy that can be lumped together under that rubric we can include school lunch reform; the campaign for animal rights and welfare; the campaign against genetically modified crops; the rise of organic and locally produced food; efforts to combat obesity and type 2 diabetes; “food sovereignty” (the principle that nations should be allowed to decide their agricultural policies rather than submit to free trade regimes); farm bill reform; food safety regulation; farmland preservation; student organizing around food issues on campus; efforts to promote urban agriculture and ensure that communities have access to healthy food; initiatives to create gardens and cooking classes in schools; farm worker rights; nutrition labeling; feedlot pollution; and the various efforts to regulate food ingredients and marketing, especially to kids.
It’s a big, lumpy tent…"
On libertarians and evangelicals:
In his 2006 book Crunchy Cons, Rod Dreher identifies a strain of libertarian conservatism, often evangelical, that regards fast food as anathema to family values, and has seized on local food as a kind of culinary counterpart to home schooling.
And more on traditionalism:
In a challenge to second-wave feminists who urged women to get out of the kitchen, Flammang suggests that by denigrating “foodwork”—everything involved in putting meals on the family table—we have unthinkingly wrecked one of the nurseries of democracy: the family meal."
(Much the rest is familiar if you’ve read Pollan before and doesn’t bear on the excerpts above.)


Ultra-marathoner Scott Jurek pushing veganism

Ultra-marathoner and vegan Scott Jurek was recently profiled in the NYT.   For those who aren’t familiar with Jurek, he’s a crazy sick ultra-marathoner who dominates many of these 50 mile, 100 mile, 100+ mile races.  The piece is unique in that it ignores the ethical aspects of veganism and just talks about athletic performance.  Let’s see what they have to say.

In college, his diet began to improve, and as he “saw how much disease is lifestyle related,” he began eating “real food, eating the way people have been eating for thousands of years.”

I’m all for real food, but claims to history in favor of real food is not an argument in favor of veganism.

“None of this is weird,” he said. “If you go back 300 or 400 years, meat was reserved for special occasions, and those people were working hard. 

Go back 300 or 400 years?  The 18th century is the benchmark of healthy eating?  To the extent people ate less meat back then it was because they were poor.

"Remember, almost every long-distance runner turns into a vegan while they’re racing, anyway — you can’t digest fat or protein very well.”

There are so many things wrong with that sentence I don’t know where to start.

  • You can get fat or protein from plant sources, so that’s just a non-sequitur.
  • Just because you’re eating carbohydrates while you’re running doesn’t mean that you’re a vegan.   It means you’re momentarily a vegetarian, I suppose.
  • And even that assumes that you body isn’t using it’s own fat or protein stores.  That’s kind of like eating an animal.
  • Also, most of these distance racers are eating heavily processed energy gels and bars — not "real food", much less vegan food.

All it takes is one look at a long-distance runner’s body to see that they have little muscle mass and they’re all skin and bones.  Hence my choice of picture.

He said he needed 5,000 to 8,000 calories a day, “and I get that all from plant sources. It’s not hard, either. I like to eat, and I don’t have to worry about weight management. All I need is a high-carbohydrate diet with enough protein and fat.”

My emphasis.  If you’re eating 8,000 calories a day, good luck getting it from fat and protein — you’ll be too full.  Interesting…to maximize caloric intake, eat a high-carbohydrate diet.  Wait, isn’t that what we’re told to do to minimize caloric intake too?  Which is it?

I’m not saying that Scott Jurek is eating the wrong way — God, no.  He’s a super-star athlete, his achievements are mind-blowing, and if he says a vegan diet helps him achieve that, then I’m not going to suggest otherwise.  By eating a high carbohydrate diet, he’s training his body to use carbohydrate as fuel, which is probably essential for his type of long-distance exertions.

But should we eat like Michael Phelps, with his 12,000 calories a day of chocolate-chip pancakes, energy drinks, and pizza?  No.  And we shouldn’t eat like Scott Jurek either.


Barefoot running taking off in NYC

Clever media people often ask me, "How do you live a paleolithic lifestyle in…New York City?"  Zing!  Oh you clever media people.  But high population density and open-mindedness can go a long way.  Here are new developments just for barefoot running: 

1. Barefoot Runners NYC now has about 175 members.  If you’re ever in NYC and want to join us, we have regular runs in Central Park on Saturday mornings at 10am and Wednesday evenings as 7pm.

2. Michael Sandler, of RunBare and author of Barefoot Running, is holding a free clinic on Wednesday, June 2nd at 6:30pm.  Nearly 40 people have signed up for that one.

3. Barefoot Ken Bob is also holding a free clinic in Central Park the following week on Tuesday, June 8th at 6:30pm.  Details here

4. We’ve had recent running clinics with Erwan Le Corre and Barefoot Ted too.

If you’re a beginning barefoot/VFF runner, or if you’re just intrigued by it and want to learn more, the two clinics are perfect places to get instructions from some of the best.  You don’t need to go out and buy any special shoes — it’s best to learn totally barefoot first.  And they’re free!