Well, I'll agree to disagree, but the show is out there shown on Channel 4 if you want to look for it. It'll back up everything I said, and they did there studies on real skinny people.
But I'm afraid its fact that muscle is easier to build from fat, than it is to build muscle from where there is no fat. I've studied this myself and read in countless places in my own quest to gain bulk and size. Everyones metabolism is different, and I could never really gain any kind of confidence from a scaled test to see how different peoples metabolism works, as you can't scale it, you need to test upon hundreds and hundreds of people. To say there is an average is scaling tests, but there are countless combinations of people in genes at different ages and stages of there life to consider. I mean half of my family is prone to obesity and finds it very easy to gain weight. My dad side however is prone to being of average weight, and yet I'm not smack bang in the middle of both? Saying that, I'm 25, so things might change when/if I get to 30.