A SELF-DESCRIBED “former fatty” who has lost 12 stone naturally has revealed the unexpected side effect no-one warned her about.

Krista was managed to – 12.5 stone – without using weight loss injections, and has documented the on her social media pages.

A woman in an olive green sweatshirt standing in a kitchen with her arms open.Krista has managed to lose 12.5 stone in weight, but wasn’t told about a bizarre side effectCredit: tiktok@krista_mm A woman holding up a photo of herself before weight loss.She admitted the side effect has made shaving her armpits a nightmareCredit: tiktok@krista_mm A person in a white top and green leggings stands with their midriff exposed, holding a phone to take a mirror selfie, with text overlay "She almost quit".She looks completely different compared to at the start of her weight loss journeyCredit: tiktok@krista_mm A woman in a white sweatshirt and green leggings takes a mirror selfie, with text overlay "She almost quit".And she has documented the journey on her social media pagesCredit: tiktok@krista_mm

And while her weight loss has led to a whole host of side effects, there’s one that left her baffled.

“Why did nobody tell me when you lose a significant amount of weight, your armpits stop being flat?” she sighed in a video on her TikTok page.

“It’s like shaving the freaking Grand Canyon now.

“And you mean to tell me that skinny people have just been walking around all of this time with super deep armpits and never said anything?”

Krista quickly found there were numerous people who could relate to her quandary, with one person writing: “The struggle is real!!!

“I lost over 100 pounds and thought this only affected me for some reason!

“It’s so hard to shave the pits now!”

“God I remember in my running era it was hell trying to shave them,” another added.

“I THOUGHT I WAS LOSING IT WHEN I NOTICED THAT,” a third yelled.

“Omg yes! & why do they make fart sounds sometimes…” someone else questioned.

“When I got skinny my arm pits got so concave I would accidentally make fart noises every time I closed my arms,” another added.

“Finally someone said this!!!” someone else wrote.

“I used to be skinny and would get dizzy and cross eyed trying to shave my pits,” another admitted.

“No problem with my puffy pits now lol!”

As others revealed some of the other bizarre side effects they’ve noticed from their weight loss.

“And lying down huuurts,” one wrote.

How do you work out your BMI, and what do the results mean?

THE BMI (Body Mass Index) is a calculation that's made using someone's height and weight.

To work out your BMI, you first need to note your weight in pounds (there are 14 pounds in a stone).

Once you have that, divide the answer by your height in inches (there are 12 inches in a foot).

Then, divide that answer by your height in inches again.

That will give you your BMI.

If you have a BMI of under 18.5, you are “underweight and possibly malnourished”.

If it’s between 18.5 to 24.9 , you “have a healthy weight range for young and middle-aged adults”.

If it’s between 25.0 and 29.9, you’re overweight.

And a BMI of over 30 means “you are obese”.

While BMI has long been used as a measurement within the NHS, there have been calls to abolish it for some time now, as it doesn’t “take into account muscle mass, bone density, overall body composition, and racial and sex differences,” researchers at the Perelman School of Medicine in the University of Pennsylvania.

“Like I’m sorry I didn’t realize how good I had it. When you have a little extra fat it’s sooo comfortable when lying down!”

“Oh my god YES!” another said.

“This and how chilly it is being skinny are my main beef with my skinny little friends now.

“WHY DID THEY NOT WARN ME?”

“What shocked me was that I lost an entire shoe size,” a third commented.

“I had assumed that my feet had grown because I had grown up.”

A woman in a black bra and skirt with a cutout at the hip.Krista describes herself as a “former fatty”Credit: tiktok@krista_mm