Maybe this woman finds more pleasure in her church and her real friends and is just using the church as an excuse to put distance on a friendship she considers superficial, empty and unreal. It isn't up to us to judge a church we know nothing about. I have friends from many dominations and they are not brainwashed. Could be that her church does teach that vanity is against their beliefs, most churches do teach that and maybe she realizes she prefers the company of real people. I for one would find it extremely boring and tedious to have to listen to a friend ranting and raving about her looks all the time. I don't associate with those types in the first place. To me they have nothing to offer a friendship except empty chatter.
As to her using the term that she isn't aging well, this does not mean she's talking about her looks or weight, my first impression would be that she might have discovered some health issues. Not everyone cares or wants to look like a centrefold in a magazine. Maybe she dropped out of WW because she found it boring to be around people who center their lives around their looks. There are more important things in life than looks and weight. As for her weight I think only her doctor would be in a position to judge if it's causing her any problems. Beauty is only skin deep and never lasts. A deep empathy and sincere feelings for a friend lasts a lifetime.