Matthew Barnett's Shortform

Matthew Barnett

There have been a few posts about the obesity crisis here, and I'm honestly a bit confused about some theories that people are passing around. I'm one of those people thinks that the "calories in, calories" (CICO) theory is largely correct, relevant, and helpful for explaining our current crisis.

I'm not actually sure to what extent people here disagree with my basic premises, or whether they just think I'm missing a point. So let me be more clear.

As I understand, there are roughly three critiques you can have against the CICO theory. You can think it's,

(1) largely incorrect
(2) largely irrelevant
(3) largely just smugness masquerading as a theory

I think that (1) is simply factually wrong. In order for the calorie intake minus expenditure theory to be factually incorrect, scientists would need to be wrong about not only minor details, but the basic picture concerning how our metabolism works. Therefore, I assume that the real meat of the debate is in (2) and (3).

Yet, I don't see how (2) and (3) are defensible either. As a theory, CICO does what it needs to do: compellingly explains our observations. It provides an answer to the question, "Why are people obese at higher rates than before?", namely, "They are eating more calories than before, or expending fewer calories, or both."

I fully admit that CICO doesn't provide an explanation for why we eat more calories before, but it never needed to on its own. Theories don't need to explain everything to be useful. And I don't think many credible people are claiming that "calories in, calories out" was supposed to provide a complete picture of what's happening (theories rarely explain what drives changes to inputs in the theory). Instead, it merely clarifies the mechanism of why we're in the current situation, and that's always important.

It's also not about moral smugness, any more than any other epistemic theory. The theory that quitting smoking improves one's health does not imply that people who don't quit are unvirtuous, or that the speaker is automatically assuming that you simply lack willpower. Why? Because is and ought are two separate things.

CICO is about how obesity comes about. It's not about who to blame. It's not about shaming people for not having willpower. It's not about saying that you have sinned. It's not about saying that we ought to individually voluntarily reduce our consumption. For crying out loud, it's an epistemic theory not a moral one!

To state the obvious, without clarifying the basic mechanism of how a phenomenon works in the world, you'll just remain needlessly confused.

Imagine if people all around the world people were getting richer (as measured in net worth), and we didn't know why. To be more specific, suppose we didn't understand the "income minus expenses" theory of wealth, so instead we went around saying things like, "it could be the guns", "it could be factories", "it could be the that we have more computers." Now, of course, all of these explanations could play a role in why we're getting richer over time, but none of them make any sense without connecting them to the "income minus expenses theory."

To state "wealth is income minus expenses" does not in any way mean that you are denying how guns, factories, and computers might play a role in wealth accumulation. It simply focuses the discussion on ways that those things could act through the basic mechanism of how wealth operates.

If your audience already understands that this is how wealth works, then sure, you don't need to mention it. But in the case of the obesity debate, there are a ton of people who don't actually believe in CICO; in other words, there are a considerable number of people who firmly believe critique (1). Therefore, refusing to clarify how your proposed explanation connects to calories, in my opinion, generates a lot of unnecessary confusion.

As usual, the territory is never mysterious. There are only brains who are confused. If you are perpetually confused by a phenomenon, that is a fact about you, and not the phenomenon. There does not in fact need to be a complicated, clever mechanism that explains obesity that all researchers have thus far missed. It could simply be that the current consensus is correct, and we're eating too many calories. The right question to ask is what we can do to address that.

Matthew Barnett5y60

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ChristianKl5y20

There are viruses that get people to gain weight. They might do that by getting people to eat more. They might also do that by getting people to burn less calories.

The hypothesis that viruses are responsible for the obesity epidemic is a possible one. If it would be the main cause literal CICO or Mass-In-Mass-out would still be correct but not very useful when thinking about how to combat the epidemic.

The virus hypothesis has for example the advantage that it explains why the lab animals with controlled diets also gained weight and not just the... (read more)

2Viliam5y

Just shortly, because I am really not an expert on this, so debating longly feels inappropriate (it feels like suggesting that I know more than I actually do). [...] I still feel like there are at least two explanations here. Maybe it is more food and less hard work, in general. Or maybe it is something in the food that screws up many (but not all) people's metabolism. Like, maybe some food additive that we use because it improves the taste, also has an unknown side effect of telling people's bodies to prioritize storing energy in fat cells over delivering it to muscles. And if the food additive is only added to some type of foods, or affects only people with certain genes, that might hypothetically explain why some people get fat and some don't. Now, I am probably not the first person to think about this -- if it is about lifestyle, then perhaps we should see clear connection between obesity and profession. To put it bluntly, are people working in offices more fat than people doing hard physical work? I admit I never actually paid attention to this.

2Matthew Barnett5y

I'm with you that it probably has to do with what's in our food. Unlike some, however, I'm skeptical that we can nail it down to "one thing", like a simple additive, or ingredient. It seems most likely to me that companies have simply done a very good job optimizing processed food to be addicting, in the last 50 years. That's their job, anyway. Scott Alexander reviewed a book from Stephan Guyenet about this hypothesis, and I find it quite compelling. [...] That's a good question. I haven't looked into this, and may soon. My guess is that you'd probably have to adjust for cognitive confounders, but after doing so I'd predict that people in highly physically demanding professions tend to be thinner and more fit (in the sense of body fat percentage, not necessarily BMI). However, I'd also suspect that the causality may run in the reverse direction; it's a lot easier to exercise if you're thin.

Matthew Barnett's Shortform

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Matthew Barnett's Shortform

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