walkitout (walkitout) wrote,

The Fats vs Carbs pendulum approaches its apex

The history of dietary advice is diverse, but at the macronutrient level, there are three components you have to work with. You cannot reduce protein below a certain number of grams or increase it above a certain number of grams without running into really serious, really obvious bad health outcomes. Whether or not man can survive on some weirdly constructed bread alone, he sure can't make it on just protein. That leaves two other macronutrients to fuck around with: carbohydrates and fats. Fundamentally, any dietary approach that can get the eater to maintain a given level of physical activity and reduce caloric input will result in weight loss (or, by reducing activity and increasing caloric input, weight gain, cf sumo wrestlers). But getting an eater to successfully work against the homeostatic forces of the body is a real tricky thing. So a lot of advice specifically cuts carbs or fats, with a goal of reducing the palatability of food and thus, hopefully, discouraging one from continuing to eat.

Which one you focus on -- carbs or fats -- is culturally influenced. There is a pendulum when carbs are the demon or fats are the demon. And we've been doing anti-carb for a long while now. Sugar busters, Atkins, paleo, etc. are all carbs are the demon diets. Science -- yeah, I know, this is going to upset you -- is a cultural activity y'all, and that means that while it tends to be a bit more rigorous than whatever your crazy uncle/aunt/friend might pull out of their respective asses, the focus of science is going to be about as blinkered as the surrounding society.


Somehow, Nina Teicholz got an opinion page in the NYT to push her new book, which is about as far out on the pro-fat end of the pendulum swing as we are about to get. She is quite careful not to name her primary opponent in this battle (Walter Willett) -- she only refers to his home base of operations over at Harvard. But you know, advocates. Whatever.

Here's where I start to feel like she's stepping over an important line.

"In 2013, government advice to reduce salt intake (which remains in the current report) was contradicted by an authoritative Institute of Medicine study."

Teicholz is doing a whole bunch of stuff here that is scary and weird and bad. First, she is arguing that this is a government driven thing, which it in no way is. The government is putting out guidelines, because they are creating a regulatory apparatus design to put a stop to the worst bullshit that comes out of the medical, nutritional and related communities. In particular, we went through a phase during which ultra-low sodium diets, sodium replaced with potassium diets, and other weirdness were killing people. What various government agencies have been trying to do is fence off the Yeah This One Is Clearly Nuts areas. Let's go look at that link she included, the IoM study itself, or at least its conclusions. After all, she is using this study to say, "advice to reduce salt intake ... was contradicted". Did the report contract that advice? No. No it did not.

"The available evidence on associations between sodium intake and direct health outcomes is consistent with population-based efforts to lower excessive dietary sodium intakes."

What the IoM changed was that aiming the gen pop for and below 1500 mg/day was definitely a bad idea, but we all knew that. And they observed the following:

"There is no evidence on health outcomes to support treating population subgroups differently from the general U.S. population."

Which means we really ought to be studying this in a lot more detail.

The introduction of the report puts the US population at about 3400 mg/day, and the government recommendation is 2300 mg/day.

"Evidence has shown that reducing sodium intake reduces
blood pressure and the risk for cardiovascular disease (CVD) and stroke."

That's hardly contradicting government advice to reduce sodium intake. What the debate is about is whether it is safe to go below 2300 mg/day (and let me tell you right now, you have to do some truly crazy things to get that low) in general, and whether particular groups (people with congestive heart disease, African-Americans with high blood pressure, etc.) should be advised to do so.

Teicholz presents this technical debate as somehow massively reversed advice -- it isn't. And a lot of the rest of what she describes in her opinion piece is similar. In a world in which the population which pays really any attention at all to dietary advice is already mad for meat, eggs, and all things "paleo", she is worried that removing lean meats from the list of healthy foods is going to encourage people to eat more carbs. I doubt it. There are a fair number of people who have never walked away from beans and grains and aren't going to start now, either because they don't _listen_ to any of this bull shit, or because they have been paying close attention to a wide range of dietary information and come to a sensible set of ideas that is best applied in their own lives.

But you know, hey, pendulum.

Altho I have to say that munging together the removal of the dietary cholesterol limits with suggesting that saturated fats are No Problem Full Speed Ahead is so deceptive that it just rankles. And while I'm all over letting people stop feeling guilty about having some eggs, I question the wisdom of pushing full-fat dairy (to be fair, as I am milk allergic, I probably am not allowed an opinion here).
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