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by Dylan16807 2132 days ago
That goes against everything I've been told about the types of fats. How much evidence is there for this?
3 comments

> When unsaturated oils are exposed to free radicals they can create chain reactions of free radicals

This seems like the most important claim and also has no citations.

I mean from an organic chemistry perspective it's obviously true. If you throw an electron at a C=C double bond, you get a ·C-C¯: which will then go ahead and bond with an H⁺ that's floating around, leaving you with a radical still bound to your initial molecule, so the theory is

    CH₃-CH=CH-CH₃ + · + ROH ⇒ CH₃-ĊH-CH₂-CH₃ + :O¯R
    CH₃-ĊH-CH₂-CH₃ + HOR' ⇒ CH₃-CH₂-CH₂-CH₃ + ·OR'
and then the · on your ·OR' restarts the cycle, and the cycle doesn't stop until you get

    RO· + ·OR' ⇒ ROOR'
which is gonna be some random peroxide that wouldn't normally form, or

   CH₃-ĊH-CH₂-CH₃ + CH₃-ĊH-CH₂-CH₃ ⇒  CH₃-CH-CH₂-CH₃
                                          |
                                      CH₃-CH-CH₂-CH₃
which is gonna be some really random molecule with who knows what effects.

Now how important this is in a biological context I have no idea. There is a plausible mechanism for it to affect cellular chemistry, but the problem is that "a plausible mechanism" and "an actual effect" are very far from the same thing, and biochemistry is complicated.

The citation I'd want to see is that the chain reactions of free radicals do something biologically interesting, or, even better, that diets high and low in polyunsaturated fats lead to significant health differences in animal models.

This reads like some nutrition grifter satire.
If you don't mind, I'm going to use "nutrition grifter" moving forward.
OP here is correct. PUFAs are the baddies. This is way too large a subject for me to even try backing up atm but I do recommend you do research into it.
Or even at least a source would be nice.