You Really Are What You Eat

(Photo: umstwit)

In a new working paper (PDF; abstract), economists David G. Blanchflower, Andrew J. Oswald, and Sarah Stewart-Brown argue that you actually are what you eat:

Humans run on a fuel called food.  Yet economists and other social scientists rarely study what people eat.  We provide simple evidence consistent with the existence of a link between the consumption of fruit and vegetables and high well-being.  In cross-sectional data, happiness and mental health rise in an approximately dose-response way with the number of daily portions of fruit and vegetables. The pattern is remarkably robust to adjustment for a large number of other demographic, social and economic variables.  Well-being peaks at approximately 7 portions per day.  We document this relationship in three data sets, covering approximately 80,000 randomly selected British individuals, and for seven measures of well-being (life satisfaction, WEMWBS mental well-being, GHQ mental disorders, self-reported health, happiness, nervousness, and feeling low).

One major note: the researchers caution that reverse causality may be an issue. That is, rather than fruit and vegetables causing well-being, it may be that well-adjusted people prefer eating a lot of fruit and vegetables. The authors recommend additional “randomized trials to explore the consequences for mental health of different levels of fruit-and-vegetable consumption.”


I also have to wonder if it’s really the increase in F&V that’s correlated with well-being, or if the F&V are displacing something else (meat? starch? sugar? fat? artificial additives? I’ll guess sugar.) that’s negatively correlated with well-being.


7 servings of fruit is a good bit of sugar.


fruits include tomatos, bell peppers and cucumbers, as well as many other parts of plants.


The second sentence in the abstract is absurd. There is A LOT of economic and social science research on what people eat! There are more than 50 departments of agricultural economics in the US. There are numerous academic journals like Food Policy, American Journal of Agricultural Economics, etc.


It could be that we "eat what we are"? I guess.

It would be interesting to see more studies on this. I have a feeling there's a mixed causality, though it's little more than a hypothesis.

That is certain foods, primarily non fruits and vegetables, are very unhealthy and cause health problems. But there may be some foods causing a negative feedback loop, while others are just plain unhealthy.

To put it another way, the stereotypical food to eat when one is depressed is chocolate or ice cream. Having the rejected woman at home with a pint of ice cream and a spoon is practically mandatory in every sit com. It's ubiquitous (but I guess that doesn't mean it's true). But feeling depressed can lead to eating these types of unhealthy foods which can lead to poorer health which can lead to more depression which can lead to more eating.

On the other hand, you don't typically think of people eating say, a steak dinner with a side of fried potatoes as this type of "depression" food. So perhaps this food doesn't have the same type of negative feedback that other foods have in terms of mental health, while still being generally unhealthy.

Maybe nonsense but who knows without research?



A stimulus (eg., chocolate ice cream) which interacts with some receptor (eg., increasing depression which increases pro-feeding activation of the lateral hypothalamus) which causes more of the stimulus to be produced/consumed (eg., eating more ice cream) is in fact referred to as positive reinforcer, and is part of a positive feedback loop.

A negative reinforcer, and negative feedback loops, do not have anything to do with punishment, or negativity in the common sense. They simply decrease the likelihood of the behaviour which elicits them.

Also, I believe there has been significant amounts of research done into the effects of stress and depression on food choices. Try Google Scholar.




certainly seems like a case of reverse causality. Happy people would seem more likely to care about their bodies and choose to put better food into it. I can't imagine a sad person being cheered up merely by fruit and veg consumption.


Perhaps there's a causal chain. Eating plenty of fruits & vegetables means you're less likely to be seriously overweight, which means you are likely to feel better about yourself. If you feel good about yourself, you're likely to be happier.


Perhaps a common causal root? Is, for instance, higher socioeconomic status associated with both higher F&V consumption as well as a higher reported/measured sense of well-being?


This is great. I am always looking for reasons to stop eating fast food and more healthy. I'll add this to my list of reasons. After all its really tempting to go hit up McD's or any other fast food joint when you are tired and hunger.


My husband and I noticed that lower socio-economic groups eat less healthy because healthy foods are expensive compared to the $1 burger you can buy at Mc D

When you add to the overall equation the costs associated with organic fruits and vegetables, you're automatically excluding lower socioeconomic groups.

Heck, I can barely afford organics and I typically go out of my way to find foods that are healthy for me but within my meager teaching budget as well.