@AlphaZance said:
@ZackVegas
Correlation isn't causation. Did you think that in one hundred years the only factor affecting public health is PUFA?
Of course the increase in PUFA isn't the only factor. There was also a massive spike in iron intake, which is also problematic, for example. There's lots of other things, from drugs to stress to quality of food that go into any long term trend. And high PUFA oils do lead to lower quality foods. Chips fried in beef tallow only have 3 ingredients.... Potatoes, Tallow, and Salt. Chips fried in high PUFA seed oils require a host of preservatives and antioxidants, due to the instability of PUFA, as compared to saturated fats.
Yes, correlation isn't causation, but PUFA is very obviously a key driving factor in the rise of obesity. We know that large amounts of PUFA slow down metabolism, and fatten animals. We know that it takes extra steps to process in Beta Oxidation than Saturated Fats, Monounsaturated Fats, or Trans Fats (that is just textbook biochemistry). We know that Omega 6 is inflammatory. And we have seen that removing PUFA in fat free diets increases metabolism, and can even cause weight loss in humans at what is thought to be a maintenence level of calories.
This is from the link your provided:
"Decrease in the unsaturated fatty acids as a result of the low-fat regimen indicates the probability that even the normal adult human subject, like the rat, is unable to fabricate the highly unsaturated fatty acids, which should, therefore, be provided in the diet.
In the light of this latter observation, it cannot be assumed that the human subject could subsist indefinitely on a diet completely devoid of the unsaturated fatty acids."
Yes, it does. But so what? The study itself showed that a human could not just survive, but significantly improve his health on a 6 month diet devoid of unsaturated fats.
The whole idea that something labeled "essential" has to be something that the body can't produce is pretty silly. For example, if blood glucose drops too low, coma and death will be the result. Yet for some reason, glucose isn't considered "essential" because the body can generate it from protein so that coma and death don't result. Again, the only issue ever mentioned from so called "Essential Fatty Acid Deficiency" is skin problems, like scaly tail in rats, or rashes or xerosis in humans.
I've cited Omega-9 made from de nuovo lipogenesis doesn't build lipid bilayers effectively. Also, research on diets high in saturated fats is that they increase transepidermal water loss (TEWL).
Don't know what studies you are referring to here, but often times, those study diets that are 'high" in saturated fat are often higher in PUFA and unsaturated fats in general. If the study used a purified diet with HCO, that would be about the only diet that contains fat with next to no PUFA, and that regiment would have to go a long way to ensure the proper vitamins and minerals that you would get from something like milkfat or beef fat in normally eaten foods.
