A nurse fat-shamed a 13-year-old. This was her mum's brilliant response.

Julie Venn, a mother from Illinois in the United States, has shared a traumatic medical experience about her teenage daughter in post that’s as ‘mama bear’ as you can get.

Oh, and it’s also brilliant.

Sharing the story on parenting Facebook page Moms of Tweens and Teens, Venn described what happened when she took her 13-year-old daughter Riley for a routine check-up.

“This week I took my 13 year old daughter to get her physical,” the mum wrote.

“I was excited to see how tall Riley would be as this year she has grown a ton! The coach in me has loved seeing her strength and size finally come along and the mom in me has loved watching this beautiful young girl begin to become a young woman.”

Riley was there to have her vitals monitored, and a nurse practitioner was doing the examination. Everything was going along as expected, but then, the nurse chose to ask a very inappropriate question.

“Tell me RILEY, HOW CAN YOU EXPLAIN ALL OF THIS WEIGHT YOU’VE GAINED?” Venn reported the nurse asked. The effect of her words were immediate.

“My daughter is speechless and her eyes begin to glass over. I am speechless and the NP goes on to explain to her that given what her previous weight was last year- the numbers just don’t correlate with her current height. Has she been eating junk food or has her activity level changed?”

It was a question that Venn responded to as any mother would.

“I LOST MY MIND. I had a literal, physical reaction,” she wrote.

Putting her hand up to the nurse to make it clear that she wanted her to stop, Venn said that it was not anyone’s place to question her daughter’s weight, shape – or body.

“She is 13, she is strong. She is healthy and she is PERFECT!”

The nurse was surprised by Venn’s reaction, and asked to speak to her after the examination, questioning her as to what the problem was.

“Our girls need to be empowered and supported and celebrated. They already have to compare themselves to the ridiculous social media bullshit standards,” Venn explained.

“Kids eat junk food! Kids sit around watching Netflix! Kids get heavier, lighter, taller, wider! ITS NORMAL!”

The mum also defended her parenting to the nurse, saying that if there was a health concern, she needed to raise it with her, not Riley.

“LAST I CHECKED MAAM I DO THE GROCERY SHOPPING and the meal preparation and the extracurricular scheduling for my children,” Venn said.

Speaking to Mamamia, Venn says that Riley was “doing great” after the experience, but as she said in the post, immediately after the incident, her daughter was “taken aback and uncomfortable”.

"Riley’s response when we left was 'Mom, this is why kids have anorexia or feel like they want to hurt themselves.' She is exactly right!"

Adding that she was glad she was present with her daughter at the time, Venn says ,"I’m not sure how she would have processed without me there to advocate for her and shut down the exchange. She knows she is strong, beautiful and perfect but when a professional you respect makes you feel less than - it’s a big deal and it hurts."

The mum says she wanted to share the story to raise awareness about how careful adults must be when they speak to children about body image.

"The reason I am sharing this is because it is dangerous," she said in her post, which she concluded by suggesting what the nurse practitioner could have said to Riley, instead.

“Know that some girls gain weight, some lose weight, some struggle with acne, some feel insecure but remember this - YOU ARE PERFECT just the way you are."

The post on the Moms of Tweens and Teens page attracted immediate, mostly positive response, with commenters commending Venn for a parenting job well done.

"You handled it very well. I think I would have spoken to the doctor in charge as well to inform them of what they NP's are saying to young girls," said one.