AITA for not helping her lose weight?

I work out and lift weights 5-6 days a week and eat a very clean lifestyle. No diet just consistency, which has resulted in me having a very fit and toned body.

I never push my lifestyle unto anyone. If the topic gets brought up is because people want to know how I achieved my physique. I don't talk about food or exercise to anyone but people stop me at the store or job just for a quick "What do you do?"

Julia is a person who has always asked for advice. At first I was more than happy to help, I invited her to the gym or on walks, until I realized she only wanted to hear about pills, supplements and vitamins to lose weight. I told her the only thing that will bring real and permanent results was eating well and staying active, I could tell that's not what she wanted to hear so I left it at that and continued with my life.

About 4 months ago I heard and saw (screenshots) some very nasty stuff she was saying about me. In a group chat, she and her friends had pictures from my social media zoomed on me to point out "the obvious" photoshop. They were saying I had gotten work done, I wasn't even that cute, and it was just my genetics.

The trash talking had.been going on for years, but now that she fell out with one of her friends, the friend sent me the screenshots.

She called me a bitch for me implying she "was lazy", when I guess one of the times she asked me how to squeeze in exercise with no time or money for the gym, I recommended she get up 1 hour early to do some free YouTube workouts or as soon as she got home to use 30 minutes for it. Mind you, SHE was the one coming to ME for suggestions. I would never overstep and suggest anything to anyone.

She said I looked down on her and would swear that I fat shame her and that's why I didn't want to help.

I just stopped talking and engaging with her online. No confrontation, no nothing. She never reached out to apologize, until this past weekend.

She sent me a message saying something like "Hey, about our misunderstanding", I read the paragraph and she basically wants to know my opinion on weight-loss shots and wants my advice. I didn't respond and now some people are saying I should help her out, since she's feeling very down on her body. AITA for not wanting to help? I don't want to talk to someone who trashed me so much for no real reason. Her friend says she's really hopeful this time around since those shots work miracles very fast and she's never felt so low on her body that she's seeking these shots that will change her life.

I've been busting my butt at the gym for the last 5 years. I don't believe in quick fixes, I don't think I'll add anything substantial. I do know she's going through an emotional time, since she just got cheated on and I'm guessing that's why she's "seriously trying to lose weight this time". Would it be cruel of me to not help?