I don't see how losing weight could in any way be construed as selling out. She was defending who she was at the time in those old quotes. But now she's grown into a beautiful woman and she's enjoying it. Nothing wrong with that.
And to answer the question, everyone sells out to some degree when entering the industry. But I don't think she's done anything big enough to call her a complete sell out. If her next album is full of Dr. Luke songs, then you'll have something.
She obviously lost weight, because it is the sensible (clearly healthier) thing to do. As for playing arenas; she probably has succumbed to doing them as to please her every-growing population of fans.
losing weight is just not about how you look, it's about heatlh too and i think her manager and other ppl around her know that..even she knows it, and now she's famous she has to be healthy.
BTW she's not selling out so stop this, she's a great artist and she really deserves all this succesful so b ahhpy for that and stop complaining about it
Maybe she just wanted to be healthier..... the weight lose could also be from her being so busy now. As for the arena she has a ton of people that want to see her, i don't think she ever expected she'd become so big in the general publics eyes and thought she'd never have a full arena of people wanting to hear her perform. And lastly for the vogue covers she was just saying that she didn't want to be on magazines for her being skinny or someone who shes not, she wanted to be on them for being Adele.
She was defending who she was at the time in those old quotes. But now she's grown into a beautiful woman and she's enjoying it. Nothing wrong with that.
Stunning. 
