I know this is not a comparative physiology topic, but this article caught my attention as I know I just ate a rather high fat meal last week for Thanksgiving and I plan to do the same throughout the holiday season.
Insulin does more than just lowering blood sugar by increasing its uptake into tissues. It can also increase blood flow to the hippocampal region of the brain to help cognitive function. This area of the brain is important in memory formation and spatial orientation. A new study published in the American Journal of Physiology - Endocrinology and Metabolism used ultrasound to measure blood flow to this region of the brain in rats fed either a normal fat or high fat diet for 6 months. Their results show that eating a high fat diet over a long period of time causes blood vessels in the brain to lose their ability to respond to insulin, meaning blood flow to the region is reduced. Because this area is so important in our ability to recall information, the researchers speculate that insulin resistance in the brain of people who are obese or diabetic may help explain why they experience cognitive impairments or even dementia.
Z Fu, J Wu, T Nesil, MD Li, KW Aylor, Z Liu. Long-term high-fat diet induces hippocampal microvascular insulin resistance and cognitive dysfunction. Articles in PresS. American Journal of Physiology - Endocrinology and Metabolism (November 29, 2016). doi:10.1152/ajpendo.00297.2016
There seems to be an emerging consensus that the active transport of glucose to the brain diminishes with aging, whereas the route for ketone bodies-the other fuel-does not. So coconut oil, a source of medium chain triglycerides (and a saturated fat!) which quickly convert into ketone bodies is being advocated for brain health and function, including avoiding Alzheimer's. What do you think of this?
If you read the literature collected from cardiovascular disease research, you will find that any saturated fatty acid smaller than Myristic Acid (C:14) will raise serum cholesterol. You might also like to know, but it sounds as if you already do, that short chain saturated fats go straight to the liver while the longer chain saturated fats go into the serum as in lipoproteins.
So I would exonerate coconut oil, but little else. The fatty acid composition of coconut oil is somewhat unique.
When I looked up insulin resistance, I found two culprits: a high-fat diet, and a diet high in heme iron. Heme iron absorption is poorly regulated and is speculated to play a role.
But frankly, the evidence that a high-fat diet leads to insulin resistance is overwhelming.
Can't win! I find that a high fat diet is the only thing that allows me to win the battle with obesity (I have other health issues which prohibit any significant exercise). Strangely, high fat/few carbs cuts hunger attacks enough that I can average fewer calories in than out, and thus slowly but steadily lose weight. It's not the healthiest diet, but 50# of extra fat wasn't healthy either. Sounds like this diet has at least one more disadvantage than I knew of.
Fat and sugar must never be consumed in the same meal. Sugar will spike your insulin. The same also happens when you consume too much refined carbohydrates.