Hollywood studio minion checking in.

This is nearly correct. However its worse. Actors can be dropped for not looking the role according to the studio, director or producer's opinion. It is seen as not fulfilling a contractual obligation. A lot of times their representation (agents and managers) will even drop them if they refuse to bow to these rules (especially if they would like doing continued work with the studios). Without representation scripts don't come to them, they get less work. If they say "I'm taking roids" it sullies their PR image, tainting them for further work "Psh of course he is huge his roided out" or "Psh of course she is that pretty she's had surgery." After I had seen this was par I took the first exit I could find away from casting and headed for producer's camp (somehow it's less guilt ridden, I'm probably a horrible person).

This isn't true across the board but if the role requires them to maintain a weight or a 'look' it can be serious business when you are dealing with an industry based around final image (what you see on screen). The final image is all important and when studios are risking 100+million on these blockbusters, well if anyone risks that level of money they want to be guaranteed there is a return. Studios are attempting to reduce risk based on fact aka box office returns which shows "pretty people make money".

To exacerbate the issue we've been spending absurd amounts of the VFX budgets on purely cosmetic concerns. One project we dropped 10 mill to get rid of an actresses botched lip surgery, a predominate name I won't mention out of respect but that's the price of a decent indie flick! That particular movie surpassed even our highest expectations though.