Here I'm referencing his 1992 hit single "Baby Got Back." His later work, such as 1994's "Put 'Em on the Glass" is significantly less progressive, unless taken as parody.
And to be fair, even "Baby Got Back" admits it's base motivations, as does any song that begins with "I like big butts and I cannot lie." But if you're willing to dig even a bit deeper, you find some real questions posed to a society that's always watching it's carb intake.
Like many people who are troubled by body image, Mix-a-Lot goes right for the rack at the checkout counter.
"I'm tired of magazines/Saying flat butts are the thing"
"So Cosmo says you're fat/Well I ain't down with that"
Notice that the artist has chosen to forgo the notion that these magazines are implying a particular physical aesthetic. No, in his view these magazines are sending us these messages directly. Their covers may not contain the words, "You, you reading this, you are fat," yet he counts their super-thin models and dieting advice as an equivalent insult.
The song, then, is best viewed as a response, a counter argument, to that insult. Mr. Mix-a-Lot isn't simply telling us what he finds attractive in this piece, he's promoting it as the only reasonable choice. In perhaps the most remarkable line, he says:
"I ain't talking bout Playboy/Cause silicone parts are made for toys"
It's such a brief statement that one could easily overlook it, but take a moment to consider what Mix is saying here. Silicon, commonly used in cosmetic surgery, is synthetic. If we choose, as a culture to find beauty in a model who we know has had synthetic implants, then we are also choosing an idea of beauty that literally isn't real.
*I find that Jonathan Coulton's acoustic version makes the underlying themes less nuanced: http://www.jonathancoulton.com/songdetails/Baby%20Got%20Back