Food Fridays: Vegetarians Are Healthier, Smarter, and Often Richer

I will start by admitting that I’m not a vegetarian. I eat very little meat nowadays, but I am not sure that I will ever be pure vegetarian.

So relax. This article is not going to be preachy; what you eat is your business.

This article is about explaining some true, but mind-boggling statistics that American vegetarians are super people. One article from Vegetarian Times suggests that vegetarians are smarter, healthier, and richer:

Furthermore, statistics suggest this educated, health-conscious, rebellious and relatively affluent contingent fits the traditional vegetarian profile.

I’ve seen many other articles, and heard these statistics countless times from my vegetarian and vegan friends. It’s almost always coupled with the message that I should become vegetarian to attain these qualities.

At a minimum, these numbers got me curious.

Are plants and vegetables truly “brain food” that help all aspects of your life?

Yes! It’s a smart and healthy diet, you stupid flesh-eater.

Vegetarian organizations are quick to reply yes. They prominently advertise the good results to promote the diet. The animal-rights group PETA has a website GoVeg.com that claims a plant diet is the best thing for kids:

Studies have shown that vegetarian kids grow taller and have higher IQs than their classmates, and they are at a reduced risk for heart disease, obesity, diabetes, and other diseases in the long run.

It makes meat-eating parents sound irresponsible.

And there’s more from PETA. Last week, star pitcher Roger Clemens denied using performance-enhancing drugs. To capitalize on the media-frenzy, PETA wrote a letter to Clemens suggesting that he show his devotion to a drug-free life by going vegetarian.

The letter goes on to suggest that the diet change could improve his performance:

Carl Lewis (named “Olympian of the Century” by S.I.) says the best year of his track career was when he went vegan, and Salim Stoudamire of the Atlanta Hawks says his game has gotten a huge boost since he cut meat, eggs, and dairy products out of his diet. Star Ultimate Fighter Mac Danzig is also vegan; perhaps he could give you some nutrition tips so that you’ll be ready for your next encounter with Mike Piazza. And if you ditch all the cholesterol and saturated fat in meat now, you’ll be less likely to keel over from a stroke when testifying in front of Congress.

All told, it appears that becoming vegetarian causes better health, improves brain functioning, and makes you an Olympic athlete.

But then why isn’t everyone vegetarian?

Is it the chicken or the egg?

Only about 3-4% of Americans identify themselves as never eating meat, poultry, or seafood, according to a poll conducted for the Vegetarian Resource Group in 2003. That’s a pretty small group.

Therefore, most people are born into homes that eat meat. To me, this situation suggests that the people who became vegetarian had to be independent, if not rebellious.

People who changed as kids would need parents tolerant to accept this choice. It might help if the parents were affluent enough to accommodate a different lifestyle—think Chelsea Clinton.

On a theoretical level, it is not necessarily true that being vegetarian causes the good attributes. It could very well be the opposite: it is healthier, smarter, and richer people who often choose to go vegetarian.

The technical term for the bias is self-selection.

Recently, there has been one study from Southampton University that showed vegetarians were smarter and healthier than non-vegetarians. The study even controlled for the self-selection bias, as reported in the BBC News:

A Southampton University team found those who were vegetarian by 30 had recorded five IQ points more on average at the age of 10.

…

Researchers said the findings were partly related to better education and higher occupational social class, but it remained statistically significant after adjusting for these factors.

Is this a victory for vegetarians?

Well, not quite yet. The problem is that a lot of the people who claimed to be vegetarian admitted that they ate chicken and fish!

So, then, are the true vegetarians smarter than these fakers?

There was no difference in IQ score between strict vegetarians and those who said they were vegetarian but who reported eating fish or chicken.

I guess it’s not being vegetarian, but saying that you are vegetarian that matters.

As far as I can tell, there is insufficient evidence to determine if smarter people become vegetarian or vice versa. It’s a classic chicken and egg problem.

Will Friday classes reduce drinking?

Any time you see a statistic, you should wonder—is it really the result of causation, or could self-selection confound the results?

This week, I read that the University of Iowa wants to reduce Thursday night drinking by introducing more classes on Friday (from WSJ):

What to do about college students who drink heavily on Thursday night? Put a price on their heads.

University of Iowa officials are so concerned about binge drinking among students, they’re offering departments extra funds to hold more classes on Fridays. The spur for that? A study that found early Friday classes reduced heavy drinking the night before.

Early Friday classes caused people to drink less the night before?

That’s wild!

I can imagine the study. They asked a bunch of college kids how much they drank on Thursday nights, and also asked whether they had early Friday class. Someone discovered that people with early Friday class did not drink as much on Thursday.

(In fact, this appears to be exactly how the study was administered—through self-reported web surveys. Here is the summary of the study conducted at the University of Missouri.)

But where’s the causation?

It’s completely possible that Thursday drinkers chose not to have class on Friday as much as possible. This would mean Friday classes would be populated with people who choose not to drink.

I remember engineering my college schedule so that I wouldn’t have to wake up in the early morning. And so did a bunch of my smarter friends. Does that mean later classes help students be smart?

Okay, so I’m slightly exaggerating for sake of argument. In respectable studies, experimenters try to control for self-selection. There are ways. For instance, you could track the same student over four years and compare drinking habits from one semester to another. Then, you would see if having Friday class affected the amount of Thursday night. By tracking individuals over time instead of comparing two groups from a single time period, you control for the self-selection bias.

The problem is that you might not have a large sample size. The alcohol study did address self-selection, and here is what the abstract says about that:

Ancillary analyses based on the subset of students who showed within-subject variability in Friday classes across semesters (i.e., had both early and late or no Friday classes) produced findings similar to those based on the entire sample.

The controlled data do suggest a causal relationship, but again, there is probably not that much data.

(And you also have to hope that students reported their drinking habits accurately.)

Nevertheless, the study was convincing enough that the University of Iowa is willing to try a new program. It will pay departments $20 for each student in each class that is changed to include a Friday class. This could mean huge money for classes with thousands enrolled.

The new policy is likely to create more Friday classes. And marginally, yes, I think that could influence responsible students to curb their drinking.

But we’ll see if the policy changes wide-scale behavior of Thursday night drinking. The policy might just cause more people to miss class on Friday, or increase in-class hangovers.

And why not look at other methods, too? If the University of Iowa serious about alcohol, it could curb drinking by looking at other behavior that is associated with less alcohol.

I can see it now: University fights drinking by banning meat because vegetarians tend to drink less.