Tightening your belt on your mind

The New York Times has an opinion piece by Sandra Aamodt and Sam Wang, Tighten Your Belt, Strengthen Your Mind, on the implications of new research on ‘willpower.’ Daniel already noted this research in his post, Glucose, Self Control and Evolution, and linked to the original research paper, Self-Control Relies on Glucose as a Limited Energy Source: Willpower Is More Than a Metaphor.

The New York Times‘ piece discusses the possibility that spending discipline necessitated by economic hard times might lead to less ‘willpower’ when confronting weight control issues. The authors write:

The brain has a limited capacity for self-regulation, so exerting willpower in one area often leads to backsliding in others. The good news, however, is that practice increases willpower capacity, so that in the long run, buying less now may improve our ability to achieve future goals — like losing those 10 pounds we gained when we weren’t out shopping.

Specifically, the research team ‘found that people who successfully accomplish one task requiring self-control are less persistent on a second, seemingly unrelated task.’ In one study, subjects were either given radishes or freshly baked chocolate chip cookies before doing a puzzle (how did they get human ethics clearance for the cookies?!). The folks who ate the radishes lasted longer and were more persistent in experimental tasks than the cookie eaters, or those who were allowed to pass on the radish appetizer.

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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.

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