This is one of those “Everything you know is wrong” posts. Werner Erhard said, “There is always enough evidence in the universe to prove anything,” and he may have been right. Many times, what seems like proof is incomplete information.
If a study shows that Vitamin C makes the fur of hamsters glossier, and other researchers want to replicate that study, they will require hamsters and Vitamin C. If the lab procures gerbils and Vitamin C, or hamsters and Vitamin D, it’s not the same experiment, so there is no good information to be had.
To reach what might be acknowledged as truth, the two parties have to be talking about the exact same thing. On the academic level, anyone looking to compare two studies of the same phenomenon will seek out studies that are as congruent as possible all the way down the line.
They want to concentrate on only one variable, so the subject populations need to be as alike as possible otherwise. In a lab, strictly controlled experiments can be done. In human life, no way.
The sedentary lifestyle has been identified as a major obesity villain and we are all used to thinking of it in that way. People who sit around a lot are less fit than people who get a lot of exercise. We don’t need science to tell us that. Every day it’s in our face. The parcel delivery person who carries boxes into the office probably weighs less than the desk jockey of the same age and gender, and that’s just how it is.
Is it a direct cause-and-effect relationship, or a coincidence? We have gotten used to taking the most simple, direct route to a conclusion: It has to be a cause-and-effect relationship. But what about people who exercise a lot and are still sloppy-fat? What about people who are in wheelchairs, yet not obese? How can any of this anomaly and contradiction be explained?
In the journal Sociology of Health & Illness, Fred C. Pampel published “Does reading keep you thin? Leisure activities, cultural tastes, and body weight in comparative perspective.” This was followed by an article in Pacific Standard that offered a more layperson-oriented view of his ideas.
Drawing on survey data from 17 (mostly European) nations, his research found “an intriguing association between weight control and enjoyment of culturally enriching but sedentary activities.” This is more obvious in certain countries, and among women everywhere, but in general, “reading and exercise appear similarly beneficial in terms of BMI.” Reading is associated with a lower body-mass index as strongly as exercise is associated with a lower body-mass index.
Is this sinking in? People who spend their leisure time reading The New York Review of Books are different from Oprah-watchers, in ways that show in their bodies. Moreover, Pampel writes:
People participating in other activities such as watching TV, socializing, playing cards, attending sporting events, and shopping have higher average BMI. Although time spent reading and time spent watching TV both expend few calories, one is associated with lower weight, and the other with higher weight.
Here’s the deal: All sedentary pursuits are not created equal. Notice, it still doesn’t imply a cause-and-effect relationship. No one says that reading more Chaucer will make a person skinny.
There are a lot of possible explanations for the resemblance. It might be a peer-group-pressure thing, which is cultural. If you hang out with a skinny crowd, there may be factors at work, like fear of being shamed, that keep you on the straight and narrow. If everybody in your Anais Nin book discussion group is thin, there is an incentive, in terms of social capital, to have a sane lifestyle.
Peer influence does not have to be blatant or even visible. It’s one of those dog-whistle things. Pampel writes:
More highly educated people tend to both read more and weigh less. Perhaps knowledge gained from schooling gives insight into the importance of proper weight for good health. In addition, mastering difficult coursework in college can help build confidence in one’s ability to reach difficult goals — including managing weight.
But this is not the whole story. Apparently, a lower BMI correlates with “reading and related activity” even when the person does not have a string of initials after their name. To say it more formally, it appears that readers are thinner “even after controlling for education and other measures of socioeconomic status.”
Or maybe it’s that people who are smart about allocating their leisure time to beneficial activities like reading, are also smart about protecting their health. They may have other things in common, like a preference for Earl Grey tea, that are not necessarily causative in either direction.