Wednesday, August 17, 2011

Deeply Skeptical of Food Reward Hypothesis Pt. III: Psychology & Obesity

Deeply Skeptical of FRH Pt I
Deeply Skeptical of FRH Pt II

The thing I dislike most about the food reward/palatability hypothesis is that it sends us into the intangible. Obviously, things like addiction, pleasure, over-stimulation, etc, exist and they are ultimately tied up with things like free will. Unfortunately, this leads us to butting up against the mind-body problem, which I find aesthetically displeasing. FRH posits that obese people are hyperstimulated by food that tastes too damn good, and is too readily available. This seems too pat, too simplistic. And not in an Occam's razor sort of way. More like a "God does not play dice with the Universe" sort of way (yes, I agree with Einstein or more specifically Roger Penrose).

The problem with introducing psychological elements into obesity is that it creates a sort of chicken and egg ambiguity. The carbohydrate hypothesis (CH) goes something like this: people eat too many simple and complex carbs (sugar and starch), this leads to chronic insulin production and high blood glucose (BG) levels, this leads to insulin resistance and cuts off access to fat stores, glucose gets converted to fat but not vice-versa, high levels of BG cause glycation (glucose modification of proteins), the pancreas gets worn out, chronic inflammation follows, obesity, diabetes, heart disease, etc ensues. There are different variations of this but that's how I'd sum up CH off the top of my head.

The nice thing about CH is that there's no talk about willpower, beyond breaking one's initial sugar addiction and getting over an LC flu. But the addiction is simply and clearly defined. This makes CH aesthetically pleasing for me in an Occam's razor sort of way.

Stephan Guyenet argues that CH is complete garbage, of course. Andreas Eenfeldt argues that it more likely needs to be tweaked. Most of the cool kids seem to be on Stephan's "side". Yes there are sides and battle lines being drawn and epithets being hurled, feelings being hurt. Anyone who's ever read anything about the history of science knows this is pretty normal behavior. Controversy and disagreement are the lifeblood of healthy science. Institutionally biased funding and a deeply flawed peer-review system are not. To this day, Anglo-Saxon countries credit Newton with inventing calculus and continental European countries Leibniz.

Stephan believes that if one doesn't prepare most of one's food at home, using traditional cultural methods, one is inevitably at an increased risk of obesity and disease (that being the cold hard truth). There's a puritanism lurking there that I find too pat, too simplistic, not in an Occam's razor sort of way, but in a teenager's opinion of politics sort of way. It also smacks of noble farmer re-enactment (yeah paleos aren't the only ones who can get caught up in re-enactment). But most of all, there's a subjectivity that I think leads to non-testable hypotheses.

We can lock some obese people in a room and let them feed ad libitum on some bland high-carb substance that tastes like powdered milk, and they could lose weight. Which has apparently already been done (although I've not read the study) and is seen as a sort of smoking gun for FRH and against CH.

We could also lock a bunch of heroin addicts in a room and let them feed ad libitum on some bland high-carb substance that tastes like powdered milk. I would bet they'd all gain weight. What would we prove by this?

Patricia writes in the comments of the last post:
Palatable food does not make people overeat or get fat.  Hyperpalatable food does.  Many East Asian cuisines are palatable, yet the people who eat them are mostly of normal weight.
OK, but I think the distinction between palatable and hyper-palatable is subjective and scientifically useless. One can just as easily argue that these hyper-palatable foods contain NADs or are addicting because of CH. Or, as the Jaminets believe, that modern, and especially processed foods, are malnourishing hence leading people to overfeed in a craving for vitamins and minerals.

Ultimately, I find FRH to be scientifically ambiguous and unappealing. Something that sounds good, like eat less, exercise more, but doesn't offer up anything beyond intangible platitudes about food tasting too yummy mixed in with pre-modern (pre-industrial) neolithic idealism and re-enactment.

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