Originally Posted by Dr. Malcolm Kendrick, Dec 11, 2019

(Defining insulin sensitivity is a) Major can of worms. I upset the likes of Jason Fung from time to time by informing him that I do not believe there is any such thing as insulin resistance. If there is such a thing, it only occurs in skeletal muscle and the liver. I sometimes think of the process as ‘trying to find somewhere to store glucose, when your glucose/glycogen stores are full.’ These stores only exist in skeletal muscle and the liver.

Anyway, imagine you have no fat cells. A rare condition that some people suffer from. You eat carbohydrates, which are converted to glucose/fructose and sent to the liver. The liver stores about 500Kcals, the the muscles store about 1,000Kcals – you are now full of ‘sugar’ and can store no more. If you eat more, the liver can only convert the sugars to fat (nowhere else for them to go), through a process known as de novo lipogenesis. Then, the fat is sent out from the liver in triglycerides (VLDL molecules). Then, it has nowhere to go, because there are no fat cells to store the fat. Then…. all hell breaks loose.

Every single person with the condition known as Generalised Congenital Lipodystrophy (no fat cells) has type II diabetes. Why, because their energy stores are full. Ergo, people who develop diabetes, do not develop it because they are fat. It is because they reach their limits of energy storage. This is not insulin resistance it is just being full.