On the Causes of Obesity: Common Sense or Interacting Systems

When you examine the data, most likely you will come to the sorts of conclusions that common sense indicated in the beginning: biology matters—some people can eat and not get heavy, others struggle with weight; what you eat matters, say fatty food versus fruits and vegetables; and how physically active you are matters.  One of the few curves thrown in might be obesity is shaped by lower socioeconomic status, but even that is not too surprising.

So, the question is not really what but why?  And that is a much harder question.

Let me first give you a laundry list of factors linked to obesity, based on my impressions of going over the research these past weeks.  They are more-or-less in order of importance: genetics, socioeconomic status, activity levels, early weight (at birth, by age seven), weight gain in early adulthood, restrictive/binge style of eating, calorie/fat dense vs. fiber/micronutrient dense foods, and social network/cognitive associations of eating and weight.  Other factors could certainly be added to this list, some perhaps shifted around, but it more or less represents an expansion on the common-sense model.

So, why?  Here are some ideas: 

-Weight gain canalizes (once you gain it, it is hard to lose it, especially for predisposed individuals)
-Activity moderates (but does not prevent—it pushes back against a tendency to gain weight)
-Early acquired eating patterns are hard to change: family and social environments affect diet habits, whether these environments favor higher calorie and fat dense foods or foods that have more fiber and micronutrients
-Food insecurity heightens excessive calorie intake and favors lower energy expenditure, especially in food-rich environments.  Food insecurity includes: restriction during gestation and abundance afterwards; restrictive/binging pattern; not having access to food, especially desired food; not eating breakfast.

Right now I am playing around with a three-systems approach to weight regulation: (1) a body-brain system that regulates energy expenditure and storage; (2) an appetite system, largely mediated by the brain but with direct influences from the body and environment; and (3) a cultural biology system, mediating things like eating patterns, body image, and expected exercise.

Continue reading “On the Causes of Obesity: Common Sense or Interacting Systems”

Good Sexual Intercourse Lasts Minutes, Not Hours, Therapists Say

That’s the title of a report over at Science Daily.  A survey of 34 sex therapists found: “The average therapists’ responses defined the ranges of intercourse activity times: ‘adequate,’ from 3-7 minutes; ‘desirable,’ from 7-13 minutes; ‘too short’ from 1-2 minutes; and ‘too long’ from 10-30 minutes.”  The researchers Eric Corty and Jenay Guardiani conclude, “Unfortunately, today’s popular culture has reinforced stereotypes about sexual activity. Many men and women seem to believe the fantasy model of large penises, rock-hard erections and all-night-long intercourse.”

For a much funnier take on the same phenomenon, here’s a YouTube music video, “Ooh Girl” – An Honest R & B Song. You can also check out our comprehensive sex round up, including the very funny Business Time video, and Greg’s in-depth post, What do those enigmatic women want?

Wednesday Round Up #5

Food, Drink and Exercise 

Eric Asimov, Can Sips at Home Prevent Binges?
Good discussion of families, teenagers and learning to drink responsibly at home

Nicholas Bakalar, Skipping Cereal and Eggs, and Packing on the Pounds
Breakfast helps keep most adolescents thin (or perhaps less hefty…?)

Ginger Campbell/John Ratey, Exercise and the Brain
Podcast discussion of Ratey’s book, Spark: The Revolutionary New Science of Exercise and the Brain, and how exercise helps the brain

UPenn Press Release, Images of Desire: Food and Drug Cravings….
Cravings, habits and memories…

UFlorida Press Release, Imaging Disorders of Desire: Opiates, Brownies, Sex and Cocaine
Interview with Anna Rose Childress

Race 

Adam Geller, Where Should Conversation on Race Start?
In our mixed reactions to Obama’s speech, and much more

Eduardo Porter, Race and the Social Contract
Diversity and investment in public infrastructure

Mireya Navarro, Who Are We? New Dialogue on Mixed Race
Navigating the tight space between racial divides

General 

Sue Sheridan, Random Bytes
Sue has her own round-up, including make-up wearing Neanderthals and the evolution of complexity

Continue reading “Wednesday Round Up #5”

Human Biology and Models for Obesity

In reviewing the research and public debates, I have come away startled by the depths of politics and misappraisal about the problem, and the need for human biology to counter this mix of science and morality.  So tonight I’ll write about three problematic things I outlined to my class today, and then show how human biology can provide a useful counter. 

Mind/body and nature/nurture dichotomies run rampant in both public and scholarly discussions of debate.  If it’s not willpower, then it is a biological deficiency.  Genetics causes obesity, or super-size-me environments.  These dichotomies are based on philosophical distinctions that are now centuries old.  They do not match up well with how our bodies, minds, and environments actually work. 

The moralization of fat and the politics of diet produce a tremendous incentive for bias, whether explicit or implicit.  Rhetorical arguments are never really rhetorical in the domain of obesity.  Results are tinged by claims of good and bad, of what’s ideal and what needs to be done.  Since thin-is-in, obesity must be bad, no matter the data; finding that miracle cure, whether it is a diet or surgery or drug, promises huge financial gains, so convenient theories are propped up. 

Suspect science results from both old dichotomies and from the moral politics of obesity.  The moral politics is heightened by the uses of science in establishing authority over a problem, whether it is the government, a medical association, restaurant businesses or soda companies. 

Continue reading “Human Biology and Models for Obesity”

‘Blind to change’ or just ‘mostly blind’?

The New York Times Science section has a recent article, Blind to Change, Even as It Stares Us in the Face, by Natalie Angier (you can access it without charge by signing up to their site). The article follows along some of the lines laid out by Jeremy Wolfe of Harvard Medical School, at a symposium on Art and Neuroscience.

Angier discusses Wolfe’s use of Ellsworth Kelly’s ‘Study for Colors for a Large Wall’ to illustrate what is typically called ‘change blindness’: ‘the frequent inability of our visual system to detect alterations to something staring us straight in the face.’ Kelly’s painting is an 8×8 grid of coloured squares, and Wolfe apparently showed repeatedly slides of the picture, sometimes with the colours of squares altered. When he first showed the slide, Angier writes: ‘We drank it in greedily, we scanned every part of it, we loved it, we owned it, and, whoops, time for a test.’ After the test, when the audience was thoroughly uncertain about its ability to recall even the basic patterns of colours; ‘By the end of the series only one thing was clear: We had gazed on Ellsworth Kelly’s masterpiece, but we hadn’t really seen it at all,’ Angier reports.

Change blindness is a fun phenomenon to put into research design. Researchers get away with some really amazing manipulations without their subjects recognizing them. Some experiments report that subjects fail to notice, as Angier details, whole stories of buildings disappearing or that ‘one poor chicken in a field of dancing cartoon hens had suddenly exploded.’

Dr. Wolfe also recalled a series of experiments in which pedestrians giving directions to a Cornell researcher posing as a lost tourist didn’t notice when, midway through the exchange, the sham tourist was replaced by another person altogether.

I’ve also seen discussions of experiments in which subjects watched a videotape and failed to notice a guy in a gorilla suit walking through the middle of the video because they were asked to pay attention to other details.

But is it that we’re blind to change, or that we just trust the world to remember for us, and we’re really good at getting the information we need?
Continue reading “‘Blind to change’ or just ‘mostly blind’?”

Encephalon at Of Two Minds

The most recent edition of the brain sciences blog carnival, Encephalon, is being hosted on the blog, Of Two Minds. Encephalon Goes to Paris (Hilton) includes a couple of references to work here on Neuroanthropology, but we do get called out on our severe reservations about twin studies (ooooo… don’t get me started…).

This won’t be news to many of you. In fact, a fair few of the visits we’ll get over the next few days will probably come from Encephalon-related browsers, but if you don’t already know about it, there’s a pile of interesting material in this edition. I won’t even attempt to summarize all the interesting stuff that you’ll find links to on everything from video games to synesthesia to the history of lithium to olfaction and sensing danger. If you’re not visiting here from there, you may want to pay a visit.