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Michelle Hoyos's avatar

Always to the point with a side of humor. Joan Breibart cuts through the B.S. of the diet industry and calls it like it is.

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David Brown's avatar

Forgive me if I pointed this out previously. Both fasting and exercise reduce the circulating polyunsaturated fatty acid load. For example, "The increased proportional intake of dietary fat, decrease in feeding frequency and increased physical activity in free-ranging compared to captive cheetahs are all predicted to result in enhanced mitochondrial FA oxidation through the lowering of circulating glucose concentrations and insulin:glucagon ratios. During fasting/refeeding cycles and increased levels of exercise, tissue PUFA concentrations have been shown to deplete rapidly in both humans and rats. These studies show that most PUFAs, including α-linolenic acid (ALA) and linoleic acid (LA), are preferentially oxidized in periods of exercise or fasting. During refeeding, SFAs and monounsaturated fatty acids (MUFAs), such as palmitic acid and oleic acid, are also more rapidly replaced than any of the PUFAs. Similarly, the concentrations of most plasma PUFAs and MUFAs have been shown to be significantly lower in rats fed a high fat ketogenic diet than in controls. The predicted increase in FA oxidation in free-ranging cheetahs is therefore likely to also skew their serum FA profiles toward lower proportional serum concentrations of PUFAs and MUFAs relative to SFA." https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0167608

So, fasting and exercise help prevent this from happening. "Fatty acid composition in the Western diet has shifted from saturated to polyunsaturated fatty acids (PUFAs), and specifically to linoleic acid (LA, 18:2), which has gradually increased in the diet over the past 50 y to become the most abundant dietary fatty acid in human adipose tissue. https://pmc.ncbi.nlm.nih.gov/articles/PMC9060469/

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