I am not a physician with an experteese in insulin resistance BUT I am a former fellow sufferer (well probably still) of the old insulin resistance and PCOS...Going on CD last time cured me of the PCOS and I got knocked up without the need for clomid which everyone said would not be possible. Since then I have had regular periods and although I gained weight the other symptoms just went away.
What I am telling you is, I can "do" protein all day long BUT I really cant "do" any - and I mean ANY sugars, also caffine in the form of coffee (which I love) doesnt do me too well either. The long and short of it is. WE have to be very careful and the weight loss on ordinary diets is so hard because of the carbs (even small amounts affect us IR types adversely and we store glycogen much easier and quicker than your average types)
Anyway
I think the answer is this....Your body needs to up it's calorific intake before training (so before the gym) so I would go for an over the counter protein shake just before your classes and stay on CD the rest of the time. Also excercising you need at least a litre and a half more water than the 2.5 Lts that the diet suggests, this is for sedentary people and is essentially the daily water we all use just breathing, sleeping and metabolising. So thats 4ltrs a day - are you doing that?
Switch your coffee for green tea - it's still got caffine in it, but its also a super antioxident, so it will flush you out.
Dont loose heart - I know my loss is really slow, but this week I am trying to sort that out.
N