She wrote on Reddit: "My friend is a personal trainer and just got engaged to another personal trainer. All of their friends were met through the gym they both work at.
"I am not a personal trainer. I [am] a US size 10. So I'm not obese, but I'm definitely on the fatter [side]."
She goes on to say she's healthy and feels happy with her appearance: "I'm very comfortable with who I am, and my doctor is too."
But the friend clearly disagreed. And it's claimed she presented the plan as though she was doing her "chubby" friend a favour.
READ MORE: • Kiwi middle-aged bridesmaid's wedding weight loss saga
"Tonight she called me with the 'best' news. Her fiancé and her are putting together a great work out and meal plan for me," she wrote.
"They figure if I drop 20-30lbs. (9-13kg), the wedding pictures will be more 'symmetric'. She was so happy and excited, like she was doing me a favour," she said.
Left "flabbergasted", the maid of honour "wasn't even sure what to say" so she hung up and hasn't responded.
"This isn't a situation where I constantly b**** about my weight and then get mad when someone offers to help.
"Why would anyone think this was okay? I honestly have no idea how to discuss this with her. I feel like it's much more the fiancé than her," she decided, adding she'd decided to opt out of the maid of honour role and wasn't even sure if she'd attend the wedding at all.
She found some validation in the bride's mother, who told her she was also shocked by her behaviour.
"She's turned into bridezilla. This is very out of character for her. Her mum emailed me last night saying this wasn't her at all, and her daughter's going to regret it the rest of her life if I'm not her maid of honour," she shared.
Reddit users expressed sympathy for the woman and she shared that soon after receiving the feedback she text the bride and told her she was throwing in the towel on the bridal party role and the invitation to attend at all.
"I talked to her, and it all came about from looking at wedding ideas on Pinterest. She has some great ideas for wedding party shots, and she 'was concerned that I would see the pictures after and be embarrassed.'
"She tried to say she really thought I was just too embarrassed to ask for help and this was the time to do it.
"I told her I've never been embarrassed about my size, why would I now? She simply didn't have an answer."
She later shared that she and her husband are going to use the money she would have spent on her friend's wedding on a cruise with their children.