This part of his response to Kevin Drum being his adorable dumbworm-infested self hits me right in the confirmation bias:
For the geeks. Yes, in truth even what I have written here is a gross oversimplification and ignores central facts such that an increase in obesity from sugar consumption must be proximately caused by an increase lipogenesis or a decrease in lypolysis both of which are hormonly regulated processess. That is, just as there is no such thing as immaculate transfer there is no such thing as immaculate obesity.
You can’t just throw organic matter at a metabolism and get fat. You actually have to create fatty acids and bind them up into triglycerides. Any model that assumes that you can is going to wind up disappointing you and of course there are a fair bit of disappointed dieters.
If Karl finds some way to get motorsports into that tag on his blog you’ll probably never hear from me again, as I’ll spend all of my time over there digging through his footnotes.
I do however have one rather large complaint about the discussion: Everything’s discussed in very abstract terms (right up until Karl gets into lipolysis and &c. at least). People “diet”, and “diets” either work or they don’t. How can you tell that someone’s “diet” — whether that means Slim-Fast or Paleo 2.0 — worked? It depends on whether they lost “weight”. Fat? Muscle? Organs? Meh, whatever. What about other interventions? Well, some people “exercise”. Maybe they do sprint-type cardio intervals; maybe they lift weights; maybe they wave a Wiimote around from the comfort of their couch. Hard telling from the discussion. From this, however, we are informed that changing one’s diet isn’t a very effective way to lose adipose tissue and that exercise doesn’t measurably improve health outcomes. Yes, the human body is ridiculously complex and gathering experimental data on fat loss is fucking hard, but that’s no excuse for sweeping all the instrumental complexity under the rug and drawing strong conclusions from dubious analyses of mediocre studies.