PUFA Depletion
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Is the 30 day no fat diet for PUFA depletion worth it or too dangerous?
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I don't think it's worth it, since it's only a “pseudo depletion”.
In animals, a diet where most of the fat was oleic acid depleted PUFAs (omegas-6 and omegas-3) faster than a diet with no fat or hydrogenated coconut oil.
If I were to try a diet for rapid depletion, it would be a low-fat one supplemented with stearic acid, since most of the stearic is converted to oleic by our delta-6 desaturase (high carbohydrates also increase its activity). The higher the ratio of Oleic to Linoleic the better
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It's quite dangerous because you will be dumping too much free fatty acid into your bloodstream. A few days of no fat is good, maybe 3 days or so, periodically. I always feel flu like symptoms when I have no fat, but it's worth it for a few days on and off.
I find white chocolate a very useful and pleasurable food. Its fat profile seems very helpful.
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Maybe someone smarter can clarify, but to my knowledge, you're not actually depleting your body stores of PUFA. You're just depleting PUFA in the blood stream. If you were eating totally fat free, you'd just switch from fat oxidation to glucose oxidation, therefore, after 30 days, there'd be undetectable amounts of PUFA within blood as you're not oxidizing any fat. But the reason the PUFA in your blood returns to baseline after a high PUFA meal is because you're switching back to fat oxidation. But you're not actually removing the PUFA in your fat stores.
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@RandomUser this makes sense.
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How about shea butter? Should be even higher in stearate.
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@jamezb46 eating shea butter doesn't appeal to me. Does it to you?
PUFA depletion works because in the background, fats are continually being burned "in place", in cells. When you don't eat fat, the fat continues to burn and over time, the PUFA is burned off without being dumped into the bloodstream at all.
Romijn, J. A., Coyle, E. F., Sidossis, L. S., Gastaldelli, A., Horowitz, J. F., Endert, E., & Wolfe, R. R. (1993). Regulation of endogenous fat and carbohydrate metabolism in relation to exercise intensity and duration. American Journal of Physiology – Endocrinology and Metabolism, 265(3), E380–E391
glucose and insulin lower entry of fatty acids into the mitochondria. Of course, this is predicted by the Randle Cycle idea. But the point is, fat is not mobilized when you eat a lot of carbs.
Background fat burning is 100g - 150g per day regardless, though. So if you've eaten a typical high PUFA diet, that will be the rate that this fat is burned assuming you have very low dietary fat consumption.
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@RandomUser the pufa fat stores take 4+ years to deplete I think. So long run it's better to just avoid pufa than to do short term fat fasting, imo.
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Interesting. So what about the study in monkeys where 30 days of a virtually zero fat diet seriously depleted their PUFA stores. You may counter that it’s not safe in humans. I would probably agree, but personally I’m 2 years into a low PUFA diet and would rather not have to wait another 4 years for the depletion to fully occur. So, you have to ask: what’s better: 30 days of suffering or 4 more years of asymptotically lower risk?
Re: the Shea butter. Well, if it tastes good why wouldn’t I want to eat it? It might be “taboo” but who cares? Stearic acid is very beneficial.
In time there is life but no knowledge; outside time there is knowledge but no life
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This “deplete PUFA in 30 days” is a pseudo-depletion and would only maintain the result if you didn't eat PUFA and if you didn't access your body fat at great/moderate intensity.
What gives fat-free this result is the up-regulation of de novo lipogenesis which dilutes the PUFA as long as the diet is maintained. I have no doubt that the amount of total PUFA decreased, but the fact that a meal replenishes levels almost everywhere already indicates a problem, probably if they put the monkeys in the study on a fast would have the same result depending on the levels of PUFA stored in body fat. When you deplete a rat of PUFA, which has a fast metabolism, it sometimes takes weeks to get it off EFAD (triene:tetraene to <0.4), not one meal.
Most studies use a fat-free diet or fat-free + hydrogenated coconut oil diet, but these are not the best diets for accelerating PUFA depletion.
