The human body temperature is 98.6 degrees F. Polyunsaturated fats have extremely low melting points. Arachidonic acid, for example, has a melting point of -56 degrees F. To put that into context, human body temperature is 113.4 degrees F cooler than boiling water. Human body temperature is 154.6 degrees F hotter than the melting point of arachidonic acid. To oxidize arachidonic acid in the body is like dipping your hand in boiling water plus another 41 degrees. Can you imagine? In order to oxidize PUFA, the body rapidly draws Vitamin E from your tissues to help combat the rapid polymerization. Do you wonder why nuts and seeds tend to be very high in Vitamin E? It is to protect the polymerization of the fragile fats. A person deficient in PUFA does not need much Vitamin E, but a person consuming lots of PUFA needs lots of Vitamin E. Factor in the average American having sky high PUFA intake AND a lack of fat soluble vitamins and you have the perfect storm of free radical damage.
No, the body cannot efficiently oxidize PUFA as fuel, and even if you are Vitamin E replete, it is going to be far more stressful to oxidize PUFA for fuel than sugar or saturated fats. It is extremely unstable at human body temperatures, unless you think dunking your hand in superheated water is pleasant
A great way to become insulin resistant is to not eat carbohydrate. A great way to become insulin sensitive is to eat a lower fat/higher carbohydrate diet. There is a reason why people that eat prolonged low carbohydrate diets eat a sweet potato, crash, then conclude they "can't eat carbs" - they're extremely insulin resistant. This, of course, can be mitigated fairly quickly by just eating carbohydrate regularly for a few days or weeks until their insulin sensitivity rebounds - this is not necessarily metabolic syndrome we are talking about, here.Well, the first thing is that LC eating rapidly induces insulin resistance. This is a completely and utterly normal physiological response to carbohydrate restriction. Carbohydrate restriction drops insulin levels. Low insulin levels activate hormone sensitive lipase. Fatty tissue breaks down and releases non esterified fatty acids. These are mostly taken up by muscle cells as fuel and automatically induce insulin resistance in those muscles.
Hyperlipid: Physiological insulin resistance