Thanks for the information gb, great read.

I read in a study that cortisol can diminish insulin sensitivity as well. I have a couple buddies that I used to lift with in the military and they're main focus was on cardio and ab work to get cut and have a six pack. They would lose weight to some degree but they had no strength and just all around looked flat. They followed a strict cardio and caloric deficient diet for 6 Months plus, it just seemed to become there lifestyle. In high school they ran cross country and were involved in track and field.

When they did attempt to bulk and try to put on more muscle they would struggle to put on any weight and would eat like a horse. I never really understood why they couldn't GAIN weight because it was so easy for me, could this be a result of cortisol having an impact on insulin sensitivity from following a high cardio low calorie regime for such a long period of time?