Insulin is mostly (in humans, not rats) a hormone signalling energy availability. That's why many humans secret insulin when we smell or taste food, way before it hits GI tract.
> Maintaining the insulin/glucagon cycle is important in maintenance of a healthy metabolism.
No point in focusing on hormones so much. I somehow don't see people fretting over their ACTH or progesterone.
> Insulin mediates glucose transport and promotes absorption of blood glucose into the liver, fat and muscle cells.
If you look at data from humans - insulin IS NOT needed for glucose absorption. Studies on diabetic people clearly show that glucose gradient into the cell is higher, not lower, despite them being incredibly insulin resistant. 1st role of insulin in humans that's critical is shutting down liver glucogenesis and gluconeogenesis.
The problem with insulin/glucose narration is omitting the role of FFA. Intracellular FFA levels drive down the glucose absorption gradient. If the glucose absorption gradient is low and we still have glucose - that will stimulate more insulin release to drive that glucose level to normal.
Problem is that as more insulin is present cells eventually start being resistant to insulin requiring more insulin for the same job. Which makes for a problem because if insulin is there to shut down liver glucogenesis and cells are now more resistant to insulin - bad news, we need more insulin to get blood glucose to same levels with a meal that used to be no problem.
Adipose tissue is simply the number #1 a-hole here because it's usually the least resistant to insulin and the least resistant to nutrient storage since it's its primary role. It will just pack more in.
P.S. Isn't Fung a quack? E.g. https://www.myoleanfitness.com/evidence-caloric-restriction/
> Maintaining the insulin/glucagon cycle is important in maintenance of a healthy metabolism.
No point in focusing on hormones so much. I somehow don't see people fretting over their ACTH or progesterone.
> Insulin mediates glucose transport and promotes absorption of blood glucose into the liver, fat and muscle cells.
If you look at data from humans - insulin IS NOT needed for glucose absorption. Studies on diabetic people clearly show that glucose gradient into the cell is higher, not lower, despite them being incredibly insulin resistant. 1st role of insulin in humans that's critical is shutting down liver glucogenesis and gluconeogenesis.
The problem with insulin/glucose narration is omitting the role of FFA. Intracellular FFA levels drive down the glucose absorption gradient. If the glucose absorption gradient is low and we still have glucose - that will stimulate more insulin release to drive that glucose level to normal.
Problem is that as more insulin is present cells eventually start being resistant to insulin requiring more insulin for the same job. Which makes for a problem because if insulin is there to shut down liver glucogenesis and cells are now more resistant to insulin - bad news, we need more insulin to get blood glucose to same levels with a meal that used to be no problem.
Adipose tissue is simply the number #1 a-hole here because it's usually the least resistant to insulin and the least resistant to nutrient storage since it's its primary role. It will just pack more in.
P.S. Isn't Fung a quack? E.g. https://www.myoleanfitness.com/evidence-caloric-restriction/