PUFAs as a Metabolic Brake

You can eat "healthy."

And still feel cold, tired, or internally driven.

Sometimes it’s not about calories.

But about the fuel system in your cells.

And about fats that can act like sand in it.

Ray Peat has a clear suspicion about this: PUFA.

These are polyunsaturated fatty acids.

Especially linoleic acid from many seed oils.

For example, canola, soybean, corn, sunflower, or safflower oil.

Why does Peat call this a metabolic brake?

Because these fats are chemically more "open."

And because they are more easily attacked by free radicals.

This can trigger chain reactions.

And from that, breakdown products can form that are very reactive in the body.

Peat describes this in everyday terms.

Oils don’t just go rancid in the bottle.

They can also oxidize in the tissue.

And Peat claims that these processes can damage enzymes and disrupt energy production.

And this is where it gets physiologically interesting.

When energy production drops, the body becomes more nervous.

Then it more easily resorts to stress strategies.

Then everything feels "on edge."

A recent mechanistic review article describes this pathway like this.

More linoleic acid can incorporate into sensitive membrane fats.

These then become more easily peroxidizable.

And that can disrupt mitochondrial energy production.

Now comes the point that often confuses people.

Not every study sees "more inflammation" from linoleic acid.

A meta-analysis of randomized studies found no clear overall effect on blood markers like CRP or IL-6.

That doesn’t automatically mean "PUFA is always harmless."

It just means the story is more complex than an Instagram post.

Peat looks less at CRP.

He focuses more on energy, oxidation, and thyroid signaling.

And he claims that unsaturated oils can disrupt thyroid function.

The practical part is the most important.

You can’t recognize PUFA by taste.

You recognize it by ingredient lists.

And by restaurant food.

Here is the data aha moment in brief.

PUFA amount comparison (USDA, household measures)

Fat source	Serving	PUFA (g)
Safflower oil	1 tbsp	10.149
Canola oil	1 tbsp	3.94
Olive oil	1 tbsp	1.421
Beef tallow	1 tbsp	0.512
Butter	1 pat	0.152

If you change only one thing, make it this.

Reduce the biggest PUFA sources.

Especially mayo, ready-made dressings, chips, fried foods, and many sauces.

And don’t make it ideological.

Make it experimental.

Do it for 14 days (or even better: for life).

Swap out seed oils at home as often as possible.

Cook simpler.

Eat more "whole foods" instead of "food-like products."

And watch three markers.

Warmth.

Sleep.

Stable energy between meals.

Best regards

Your Raw Animal Team