Is there an optimal level of bodyfat one should be before commencing AAS?

I was thinking about it today, insulin has a tendency to favor shuttling sugars to fat cells in obese people. Extra fat would cause a higher conversion rate to estrogen in obese people.

Am I right in my thinking? Are there other factors at play?

I guess its also obvious that someone who is obese wouldn't have the greatest diet in the world, but I am wondering about the physiological issues.