Fibre and Saturated Fat

Something else I don’t understand about the standard nutritional guidelines:

• FibreIndigestible carbohydrates. Typically distinguished as soluble and insoluble. Conventionally 'indispensable', but neither in the literature nor in my experience truly 'essential'. There are occasions where they can be beneficial. → more == good
• Saturated fatFatty acids with no reactive molecular component — normally solid at room temperature. Typically animal fats. → more == bad

The recommendation goes: eat fibre so your gut bacteria can produce short-chain fatty acidsFatty acids with fewer than 6 carbon atoms, as opposed to medium- and long-chain fatty acids. → more from it - like butyrate (butyric acid), acetate (acetic acid), and propionate.

So which is it?

These short-chain fatty acids are, chemically speaking, 100% saturated fats - the very thing we’re always told to avoid.

The irony: the body values these fats so highly that the cells lining the colon wall (colonocytes) derive about 60–70% of their energy directly from butyrate ^(*).

So the human body is physiologically built to run on saturated fatty acids. The detour through fibre is essentially just a method for producing saturated fat “from the inside”.

Butyrate? Butyric acid? That sounds like…

Butyrate is found in highest concentration in butter fat in nature (which is also where the name comes from). Anyone eating butter is taking in the finished end product that bacteria would otherwise laboriously build from fibre - provided you have the necessary bacterial strains aboard in sufficient numbers.

Anyone who keeps their body in the fat-burning zone and ketosisMetabolic state in which the body burns fat rather than glucose for fuel. Characterised by a measurable level of ketone bodies in the blood. → more also produces ketone bodies - among them β-hydroxybutyric acid. And ketosis is something the standard guidelines really don’t like. It’s effectively prevented by the standard advice to “get more than 50% of your energy from carbohydrates”.

Biochemists will object: “Wait! Short-chain fats from the gut behave very differently in the bloodstream than long-chain fats from a steak! And butyrate from butter is absorbed in the small intestine before it ever reaches the colon.”

Fair enough. There are physiological differences in the transport pathway. But none of that changes the fundamental evolutionary irony: the very fatty acid family the body uses as premium fuel at our most important barrier - the gut wall - to suppress inflammation, is chemically 100% saturated. If that molecular structure were inherently toxic to the heart and cells, this system would make no sense.

What nobody has been able to explain to me so far: Why is butyrate from fibre celebrated as “anti-inflammatory”, butyrate from butter classified as “harmful to the heart”, and butyrate from ketosis condemned?

More about fibre and saturated fat

Evolutionary Association, Chapter 1: The Composition of Body Fat

Your love handles are a food diary of the last few years - and many of the entries come from the deep fryer.

Fibre Against Constipation?

Jammed roads and a jammed-up gut get treated in completely opposite ways. It turns out - to absolutely no one’s surprise - that ‘more traffic’ doesn’t clear congested traffic

Good Carbs, Bad Carbs

The usual split into ‘good’ and ‘bad’ carbohydrates is a convenient shorthand, but my version of that scale looks different: The bar for ‘good’ is higher.

Fibre: Necessary or Unnecessary Ballast? A Self-Experiment

The literature doesn’t list fibre as essential, yet standard guidelines treat it as indispensable. A self-experiment, with a surprising outcome.

Saturated Fat

Schrödinger would have had a field day with the contradictory claims about whether saturated fat is harmful or beneficial. My take: ‘Everything is better with butter’

Sunburn and UV

A surprising side effect of switching to a ketogenic diet: a new built-in sun protection factor

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