Thanks again for all the links and info, I love this stuff and it'll no doubt keep me busy.
Re: insulin resistance - to be perfectly honest, I've never been tested and it's my own 'self-diagnosis' simply based on (lack of) results in a controlled environment (i.e. training, strict dieting, etc.).
I have an extremely tough time adding lean muscle tissue despite having the necessary precursors in place:
Reason to adapt/grow: (i.e. intense training)
environment for growth: (i.e. caloric surplus, quality proteins/carbs/fats etc.)
Sufficient rest (questionable as to what would constitute 'sufficient', but I suppose it's rather individualistic)
However, I continue to put on bodyfat very easily. What really opened up my eyes to insulin resistance being my issue was one study (which I'll try and find) which had a single sentence that was like an epiphany for me. Paraphrasing:
"Fat cells tend to maintain their sensitivity to insulin even when muscle cells become resistant..."
This was a big 'eureka!' moment for me, because prior to this, I had no logical explanation for why my body wasn't responding favorably to training and eating to grow muscle.
I'd be very interested to hear your thoughts on this, thanks!