Anorexia and crack can keep some of them thin.
Yes, but I am not talking about pornstars who are "just thin", I mean I am thin naturally, I have good genes, but today it is not enough to be thin, you have to be toned and have perfectly chiseled muscles and it's not enough to be thin, everything has to be shaped just right.
For example stars like Bitoni and Hunter Bryce have a lot of muscles, you can see the line in the middle of their abs and they have defined calves. Anyone can be thin, even I am thin. You have to be thin but with curves in the right places and have the hip bone go out, not be thin like a stick. Just because someone is thin does not make them have a hot body, the waist has to be thin but it has to be curvy like Amy Reid.
I am really curious to know what Amy Reid and Audrey Bitoni do.... They are not just "thin" (which is not hard to achieve) but thin in all the right places and meat in the right places with definition and muscle tone.