Clarification On Palmatic Acid, Fat And Sugar Metabolism And The Randle Cycle

[Dr. C]

I have a concept on my mind about SFA and would be glad if you you comment on it or confirm it.

Large studies sometimes are saying that saturated fats (SFA) are causing diabetes and cancer. As far as I understand, this is not really the case. Only palmatic acids blocks the oxidation of fatty acids (FAO) if eaten in concentrated form. Nevertheless, this may happen on Western diets (which combine lots of carbs) on a frequent basis which leads to the result of the studies .

If FAO is blocked the cells can only oxidize glucose. BUT if a lot of fat is eaten (lot of free fatty acids in the blood) the Randle cycle becomes active and makes all cells insulin resistant. If this is done often, diabetes can develop. Also for the next few hours all cells will become energy deprived as neither they can take up blood sugar due to the Randle cycle nor does FAO work. This may cause cancer on the long run as cells need to get their energy from somewhere and now switch to glycolysis .

This problem can be migrated by
- either eating just very little fat and lots of carbs (Ray Peat style)
- or by combining palmatic acid with either olic acid or steratic acid who both seem to outbalance the FAO deprivation.

Do you agree so far on me?

I have some open questions on that:
- Ray Peat recommends eating a lot of daily fat which may include more palatic acid then steratic acid and only a little olic acid. Still this seem to do no harm. Why?
- it may not be advisible, but it is possible to survive on no carbs, a little protein and lots of fat (aka keto). If the fat is SFA with mainly palmatic acid (eg cream), these people still seem to burn a lot of fat although their FAO should be blocked by the palmatic acid. Is a rest of 10% FOA for them enough? Or do they trigger cortisol which then leads to gluconeogenesis from circulating triglycerides and the new glucose ends up on glykolysis?
- the respiratory quotient leads to the fact that it is possible to generate up to 100% of all energy from fat only (respiratory quotient of 0.7). Can this only happen in a fasted state as the body adipose tissue includes enough steratic acid to make the mitochondria and FAO work?

 

[Hans]

Only palmatic acids blocks the oxidation of fatty acids (FAO) if eaten in concentrated form.

Not really. It only blocks excessive beta-oxidation by generating reactive oxygen species in the electron transport chain which inhibits the enzyme aconitase. This increase malonyl-CoA, which inhibits the carnitine shuttle and limits fatty acid availability for beta-oxidation. This is good.

If FAO is blocked the cells can only oxidize glucose. BUT if a lot of fat is eaten (lot of free fatty acids in the blood) the Randle cycle becomes active and makes all cells insulin resistant.

Insulin shuttles fat into adipose tissue so that fats don't interfere with glucose oxidation. However, if lipolysis is still active even under insulin signalling, you'll have high free fatty acids and glucose at the same time, and then you get trouble at the mitochondrial level. This occurs when a high PUFA diet is eaten because PUFAs stimulate lipolysis. Lipolysis should only be active when inulin is low, and insulin is usually elevated 4+ hours after a carbohydrate meal. So for 4+ hours, lipolysis should be inhibited. But this is dependent on how insulin sensitive someone is, the kind of food eaten, etc.

Saturated fat, when oxidized through beta-oxidation, will generate enough ROS to make the cell just insulin resistant enough so that glucose don't flood in and overload the cell. This is protective. Fats and glucose should not be high at the same time in the blood. Postprandial, insulin shuttles fat into adipose tissue and glucose into cells for storage or oxidation.

Also for the next few hours all cells will become energy deprived as neither they can take up blood sugar due to the Randle cycle nor does FAO work.

Only insulin resistant cells cannot uptake glucose, not because of the Randle cycle. And cells will not be energy deprived because it will be burning fat if glucose oxidation is inhibited by the Randle cycle.

This problem can be migrated by
- either eating just very little fat and lots of carbs (Ray Peat style)

This is a good experiment to do and see how you react to it.

- or by combining palmatic acid with either olic acid or steratic acid who both seem to outbalance the FAO deprivation.

Stearic acid will inhibit the carnitine shuttle just as well as palmitic acid, but neither will inhibit fat oxidation. Palmitic acid actually increases glucose oxidation, so the cell will definitely not be energy starved. PUFAs inhibit glucose oxidation while also activating uncoupling, thus reducing ATP levels, and then glucose cannot step in an make up for the loss in ATP, because PUFAs inhibit glucose oxidation. SFAs also increase uncoupling, but also increase glucose oxidation to make up for the loss in ATP production. SFA = good.

Ray Peat recommends eating a lot of daily fat

No, he also says that you can eat more fat if you're very active, else fat should rather be kept on the low side.

I think your confusion is that palmitic acid inhibits fatty acid oxidation, but it only prevents excessive beta-oxidation, which is good.

 

[ecstatichamster]

Dr. Peat has said that the digestion works better when there is a bit of fat with your carbs and protein. A mix of all three helps digestion.

And that counts for something, doesn’t it.

 

[Hans]

By keeping fat on the low side, I meant like around 60g a day. Sorry I should have clarified. But I'm not making recommendations to shoot for that specific number.