"She would start comparing my body shape with other girls. She would never say, 'You're fat,' it was more like, 'Oh, you're quite heavy today' when you were being spotted on a routine.
"I was 15 years old being compared to pre-pubescent girls."
The coach was approached for comment on a number of allegations last week, but has declined to comment.
North Harbour Gymnastics chief executive Mike Thompson described the allegations about the club as "gut-wrenching".
Poppy breaks down as she tells her story. The experience still weighs heavily upon her.
"Gym was my life. If my gym wasn't going well, my life wasn't going well. My experience has affected me in a lot of different ways, especially with regards to my body image.
"I am super-wary about developing relationships. I'm told a lot of people think I'm a bitch when they meet me because I take so long to warm to people."
She didn't want to share her story because she hasn't even told her close friends about her eating disorder.
"It's very personal. I ended up resenting gymnastics and don't like to remember that time of my life. But I've seen other people have the courage to talk, and I think I know a couple of them, so I feel a responsibility as well.
"It was very hard for me, just a dark, dark time. I literally cannot look at pictures of myself from that time."
She was also lucky. Her mother recognised the symptoms of bulimia early. Poppy was taken to a psychiatrist and then referred to a specialist. She has the bulimia under control, though says she still struggles with body-image issues.
"I was consumed by losing weight. I was consumed by trying to look perfect. That obsession was what made me good at gym but it also led me down this path."
She describes her last six months in the sport as "hell".
No matter how hard she tried — "I worked my arse off" — she could no longer please the person who mattered most.
"I felt it was all my fault. If I could just get better, I would make her happy," she says.
"The gymnastics mindset is to never give up. We're all extremely resilient and I wanted to live that. I could fix it by getting the coach back onside, getting her back to the person who used to buy me birthday presents and respect me."
Something was permanently broken, though. Her skills had regressed; she no longer had the courage to attempt moves like she once had, so she wouldn't.
"I didn't leave because I wanted to. They said they couldn't have me in the programme behaving like that. I was not important to her once she could no longer use me to make her look good."
It's only now that Poppy realises how sick the culture is and how desperately it needs to change.
"I know a girl who broke an arm and was too scared to tell the coaches because she'd just get told she was stupid.
"'What were you doing?' was always their first response to an injury, not 'Are you okay?'"
She's out of there now and is better for it. Life is slowly improving. And the coach she once used to idolise?
She'd be happy if she never laid eyes on her again.