Be Happy, Eat Fruits and Vegetables

By James Kwak

From the treasure trove that is the NBER working paper series, a friend forwarded me “Is Psychological Well-Being Linked to the Consumption of Fruit and Vegetables?” by David Blanchflower, Andrew Oswald, and Sarah Stewart-Brown (NBER subscription required). It got some media attention last month when the paper first came out, but I wanted to read it because, well, I eat a lot of fruits and vegetables: I generally aim for seven servings a day, although when life is busy it can be as low as three or four. (Right now I’m munching on dried mango slices.)

The core of the paper is a bunch of regressions that show that better psychological well-being (which is all the rage these days) is correlated with eating more fruits and vegetables, with benefits up to at least five servings and in some cases up to eight servings. This isn’t particularly surprising on its face, since eating fruits and vegetables is probably correlated with having a high income, exercising, being fit, cooking, and any number of other things that are conducive to happiness.

But the relationship persists even when you control not for the usual things—age, gender, race, marital status, income—but even when you control for things like education, religion, health status, body mass index, smoking, sexual activity, exercise, marital status, number of children, disability status, and employment status. (See Table 1, column 3.) This is surprising, at least to me, since it says that fruits and vegetables make you happy in some way other than making you healthier and more fit.

It’s still quite possible that the mechanism at work isn’t the fruits and vegetables themselves but something else that correlates with consumption of fruits and vegetables. I suspect that people who eat fruits and vegetables tend to be those with more time on their hands (even within the group of employed people) and who put more effort into taking care of themselves. But just in case it is the fruits and vegetables themselves, go eat an extra apple or banana. We already know that eating less meat is good for the environment, anyway.

20 thoughts on “Be Happy, Eat Fruits and Vegetables”

  1. I don’t know. My diet has substantially consisted of vegetables and fruits, plus grains and beans, for the better part of a dozen years and as far as I can tell I’m still mired in the same funk as ever.

  2. Maybe the causation goes the other way, and being unhappy causes you to eat chocolate instead of veggies.

  3. Fresh Fruits and Vegetables provide compositional nutrients, fiber and energy without “storage deposits”, and generally are not eaten in excess in their “natural” packaging. If it were just a matter of 7 fruits, fruit salad would be all the rage…
    …of course long range pesticides and genetic manipulations will undoubtedly complicate such findings over future developments and “market” factors interfere with Mother Nature’s nurturing gifts.

  4. @Jay: …interesting point!
    It is difficult to say whether one is unhappy because they don’t eat vegetables and fruits, or they don’t eat vegetables and fruits because they are unhappy. It would make an interesting follow-up study to see if changes can be determined with a control on dietary composition alone.
    On the other hand, I have found myself becoming very unhappy because i can’t afford my favorite Steaks!

  6. Having been rich and poor a few times in my life, I can attest that fresh fruits and veggies are completely cost-inaccessible to a family on a budget, which is fully half of our proud country these days.

    Just out of curiousity, somebody should correlate the “happiness” of eating fresh produce with the divisive election results…

  7. Harvey, I´m sorry but I have to disagree. There is nothing cheaper than vegetables and fruits. But you have to have also the other variable, which is nutrition of your body. Of course that you can buy a fast food for a lesser price, but if you are educated and do the counting of the nutritional value, then you come to a conclusion that grilled leak or broccoli soup prepared at home is much cheaper than the fast food.

    However, the quality of the vegetables and fruits changes with the income level. This is for sure. And with all those pesticides, poisons and GMO´s, it is sometimes scary to admit that. But you have to eat something, and by eating meat or animal products, you would not do much better. Animals are genetically mutated, doped with hormones and steroids and they also eat the grains.

    The solution I would like to see in the future is already existent in some parts of Canada and US and its called Fresh City Farms. This project has many advantages: It promotes local employment, it delivers fresh fruits and vegetables every day, it is without chemicals, it is sustainable in terms of energy, and can provide cities or regions with fresh food in times of crisis (like Sandy, earthquakes etc.).

  8. @johnberk – I was thinking along the same lines, except I was going to be a lot more snarky and make the SCIENTIFIC observation that unless a person participates in the whole process of going from seed to table, the *majik* of fresh food does not work. Seriously. Yet another book to co-author since I did not get enough votes to be Prez so Plan B :-))

    Hey, I thought they were all rich and VERY happy sitting behind their screens as Masters of the Economy while licking their secret silicone lollipops coated in high fructose corn syrup and sprinkled with meth and/or cocaine that gives them that nanosecond edge for profit-taking…?

    Lord knows all those algorithms were not derived from the science behind the existence of fruits and veggies.

    But, whoops, you’ve been punk’d. Keeping the electricity turned ON so that your billion dollar gizmos work was not our job. We took the $$$$ and ran.

  9. At the risk of bringing some science to this discussion, I commend to you:
    http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1781416/

    Here’s a HuffPost article about a recent Department of Agriculture study that’s on point:
    ttp://www.huffingtonpost.com/2012/05/16/healthy-food-expensive-junk-food-cost_n_1521882.html

    This one addresses the environmental “footprint” of meat vs. vegetable, not specifically on-topic but certainly relevant:

    Click to access es702969f.pdf

  10. @publiustex – grandma’s sister, who got stuck in USSR *empire* after the curtain fell, survived by squatting on an abandoned spit of land and skanse too near the railroad tracks quite a ways outside the nearest city to her in Byelorus. That’s how she survived for the rest of her life – only on what she could wrest from that bit of land she commandeered for herself in the chaos that ensued (and no one ever challenged her right to EARN a life with her bare hands) and from chickens and a goat for cheese and milk. Before the “ism” revolution funded by weapons manufacturers arming the criminal element of the peasants and big city rabble so that they could go get the gold, she and her sister would have inherited a farm almost the size of Rhode Island with over 30 thriving villages that busied themselves with agriculture during the growing season and then fired up the kilns and ovens to manufacture some of the highest quality goods the world ever had – ovens which also heated their homes and barns through the winter due to some elaborate *science* understanding of how hot air can be directed..

    So you did not come up with any *science* that hasn’t already been around for 10,000 years or so on this planet in any bonafide *civilization*. Nothing new in the way of *genius* in your links. But thanks for the lecture.

    Now why Alabama, with so much fertile land under it’s feet, can’t provide fresh fruit and vegetables to it’s population might have a lot more to do with another “ism” that consistently broadcasts the political opinion that not everyone *deserves* to own a spit of land and a decent shelter to call home and have nothing whatsoever to do with a man to land ratio that is sustainable.

  12. I made myself some semi-burnt turkey sausage and threw in some carrots with it while it was cooking. Does anyone know where this fits on the spectrum??

  14. As a small family fruit farmer (with merely an interest in economics) perhaps I am a little closer to the ground than many here in regards to one issue that has been mentioned in a couple of comments. You should know that the use of broad-spectrum pesticides in the production of our products (apples, pears, and cherries) and their negative effects as they may pertain to this discussion has been greatly reduced over the last few years. Integrated Pest Management, with its increased reliance on natural predation has become the norm with fantastic results. As great strides are being made on the farm towards a more healthy food supply, I thought I would take the opportunity to share.

  16. FWIW, there are too many variables in this type of experiment for it to be taken seriously. I am all for eating fruits and veggies (Michael Pollan makes the most sense to me of anyone on this subject) but there is no way to control for important variables like childhood experiences, epi-genomic phenomenon, lack of sleep the night before a questionnaire, etc… I am not against attempts to study “positive psychology” but I find it a bit like studying the effects of drugs that may have marginal effects upon a condition – effects that can hardly be “quantifiable.” In academia there is a “publish or perish” reality (I know I lived there for decades) and this results in a lot of crap science being lumped in with a lot of great science. But in experiments where there are a lot of parameters that can neither be controlled for or accurately recognized one should be properly skeptical of the results and impressions derived.

  17. Logic has a point. And then there’s this other mind-bending source of doubt, cosmic habituation:

    http://webcache.googleusercontent.com/search?q=cache:OB9SSKGfPlYJ:www.science20.com/alpha_meme/science_precognition_cosmic_habituation_and_decline_effect-84694+cosmic+habituation+wikipedia&cd=2&hl=en&ct=clnk&gl=us&client=safari

    http://www.radiolab.org/blogs/radiolab-blog/2011/may/03/cosmic-habituation/

    http://www.newyorker.com/reporting/2010/12/13/101213fa_fact_lehrer

  18. I love Costco, but I hope you’re eating the Trader Joe’s unsweetened dried mangoes instead of the Costco ones with added sugar. The unhappy sugar will cancel out the happy fruit!

  20. the proof is that we were meant to omnivores. Never mind that you didn’t proivde any proof whatsoever, any studies or anything. The paragraph I posted is based on studies that apply to how people live today, if a person decides to eat healthier and becoming vegetarian is just a side effect what does that have to do with anything? If in this world, for some people, the only way to be healthy is to avoid meat then that isn’t against anything I have said so far either. As for your claims concerning vegetarians, again show me a reference to anything or I don’t see why I should believe it. I’m not going to take the word of a stranger on the Internet for it. additionally your claim regarding primates being e2€œvegetarianse2€9d is false. unless you done2€™t consider insects being from the animal kingdom. many primates in captivity suffer from lack of b12, because theye2€™re not getting it from the insects they regularly digest along with their fruits and veggies.You don’t understand what my claim was. If you compare the diet of apes to the diet of man, they are adapted to surviving on a meat free diet while man is not. I can’t make it any clearer than that. However this was not my claim, the OP implies that the human body cannot absorb proteins and carbs without meat, when this is clearly false. The proof lies in the survival of apes, as well as various personalities that are known all over the world. Such as, Ghandi, Anna Paquin, Kate Bush, Yehudi Menuhin, Voltaire, Pythagoras, Diogenes, Newton, Da Vinci, Thoreau, Shaw, Tolstoy, Naomi Watts, Mark Twain, Brooke Shields, Bob Dylan, Woody Harrelson, Martin Luther, Schopenhauer, Weird Al Yankovich, Grace Slick, Benjamin Zephaniah, Farin Urlaub, Killer Kowalski, Andreas Cahling, Leonard Nimoy, William Blake, Anne Hathaway, and so on. PS: You can get B12 by eating eggs, eggs are not meat so once more, this is completely besides the point and shows that you either know very little or think you can fool me.

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