Rule One: No PUFAs

I have no good reason to avoid PUFAs, but I am suspicious

There's absolutely no reason to believe that PUFAs (polyunsaturated fats/seed oils/vegetable oils) cause weight gain.

The Molds address this here:

https://slimemoldtimemold.com/2021/08/18/a-chemical-hunger-interlude-e-bad-seeds/

And Scott Alexander (whom I tend to trust on matters of assessing medical literature) addresses the idea here:

https://slatestarcodex.com/2020/03/10/for-then-against-high-saturated-fat-diets/

Both come to the conclusion that lots of experiments have been done on saturated fats vs polyunsaturated fats, and that you can easily support the conclusion that one or the other causes weight gain by picking a few favourites.

The overall state of the literature, according to these two random guys on the internet, is that there's really no signal in the literature at all.

And that's exactly what you'd expect if there's nothing really there.

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And yet I am suspicious.

Almost everyone seems to agree that the omega-6/omega-3 ratio is important, and that the ideal ratio is about 4:1.

Modern vegetable oils from seeds are almost entirely omega-6 fats.

If both those things are true, then vegetable oils kind of have to be bad for you. Just through buggering up that ratio. That doesn't necessarily mean that they cause weight gain. But they have to be messing things up.

We were evolved to live on animal fats and fruits and things like that. No ancestor of yours for a very long time went around getting most of its fuel from eating vast quantities of the tiny seeds of flowering plants.

If you take a metabolism that was designed to live on roughly a 50/50 mix of saturated fat/monounsaturated fat, and ask it to run on polyunsaturated fats, that is unlikely to go well.

Consider what happens if you try to run a car engine on diesel, or a diesel engine on petrol.

Also, we are mammals! So the types of fats that exist in human milk should be great for us, at least when we are babies. And my proto-indo-european ancestors seem to have conquered the world from Britain to India simply by retaining the ability to digest milk into adulthood.

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There is yet another anti-seed-oil argument that goes: Vegetable oils are extremely unstable, and if you heat them up, they degrade into all sorts of nasty things like aldehydes.

You don't want to be eating aldehydes.

Commercial frying involves heating up vegetable oils to very high temperatures, and keeping them there for a very long time.

Incentives to change the oils are not strong.

Incentives to keep using the oils way past the time when they've suffered significant degradation are strong.

Your chips might as well have been cooked in varnish.

Maybe seed oils are bad, per se. Maybe seed oils are bad if they've been heated up or allowed to go rancid.

And yet another argument is that most experiments done on the saturated fat vs unsaturated fat question have been done with lard (pig fat).

You would think that lard is a straightforward animal fat.

But modern lard comes from pigs that have been feed on seed oils.

Neither pigs nor humans can digest seed oils and turn them into animal fat. The polyunsaturates stay polyunsatured and are incorporated into the fat.

Modern pig fat, chicken fat, and human fat contain quite large quantities of polyunsaturated fat.

The only animals that can actually digest the polyunsaturated fats and convert them to the saturated fats that animals should be made out of are ruminants (cows, sheep, goats..)

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So I'm going to avoid eating anything with significant polyunsaturated fats in it.

As I quickly discovered, this involves avoiding almost all processed foods. They sneak vegetable oil into absolutely everything.

Luckily absolutely everyone is convinced that it's a good idea to avoid processed food.

Although it seems that no-one can tell me what is a processed food (hummus? bread? cheese? peanut butter?), or why processing a food would make it bad for you.

My decision procedure is 'if it contains a high-PUFA oil, then I'm not going to eat it'.

So this rules out hummus (sesame oil) and peanut butter (peanut oil), both of which I'm going to miss, as well of lots of ghastly supermarket ready meals which really aren't very nice.

Most bread seems to contain rapeseed oil. But there are still some types of bread available which are just made out of flour and yeast. So I'm only going to eat those.

Unfortunately, it also seems to rule out pork, ham, chicken and bacon.

But beef is ok, so lots of beef and dairy for me.

For completeness, I'm also going to renounce olive oil and palm oil, which also have fairly large amounts of PUFAs in them.

I can't really believe that Olive Oil is bad for you. Southern Europeans have been eating it for literally thousands of years.

But goddamn it, if one is going to believe in fairies, one must believe in proper fairies.