I don't really agree here. Overfilled subcutaneous fat cells leading to fat being deposited in liver and other vital organs, leading to insulin resistance is a pretty plausible chain of causation. After that, increased peripheral exposure to insulin due to central (liver, pancreas, brain) insulin resistance might drive fat gain further.

A thinner person might get type II diabetes, and there are situations where some difference in individual genetics etc. may cause this. But a lot of people who aren't all that fat, but who develop type II, may still be "fat" in the sense that their personal subcutaneous fat limit before fat trapping is compromised and fattening of the liver and pancreas becomes more likely to has been met--some Asian groups becoming diabetic at a lower bodyweight than people from a background more prone to fat gain is an example here.


From the side of weight loss--I do think insulin resistance (as long as it's not of the fat cells themselves) can certainly interfere with weight loss itself, since by definition the insulin levels will be much higher than they needed to be to stimulate most of the fat gain in the first place.