A 21-year-old is warning that gastric bypass surgery is not the easy option to lose weight and that there can be side effects.
Nicole Donald had to go on a feeding tube and drip after the surgery left her dehydrated and malnourished.
The number of young adults opting for the surgery has risen slightly, but is still a tiny number with only 12 operations conducted last year on people aged between 20 and 24, up from five in 2015 and nine in 2016.
She told the Herald on Sunday she is only able to eat about five to six teaspoons of food per meal before vomiting and had been in and out of hospital since the procedure on February 1.
"It's hard. I've got no energy."
Donald, who lives in Waiouru, is speaking about her experience to let others who are considering the same surgery know about the potential side effects.
Gastric bypass surgery involves reducing the size of the stomach to a small pouch and putting in a bypass that shrinks the small intestine by about a metre, which restricts food intake and makes patients feel full after eating small meals.
After Donald was hospitalised for dehydration, doctors ruled out surgical error and believed she would be able to eat more after her body adjusted to the change to her digestive tract.
Despite being frustrated by its side effects, Donald didn't regret having the surgery.
"It's changed my life," she said.
Before surgery Donald weighed 126.5kg and had a BMI of 43.5, meaning she was considered morbidly obese. She now weighs 95.5kg and hopes to lose about another 20kg.
Donald said she had been pre-diabetic, was diagnosed with polycystic ovarian syndrome at 13 and had used alcohol to self-medicate and cope with anxiety.
"I'd tried so many things [to lose weight] - going on Weight Watchers, I started at the gym and had a personal trainer," she said.
"It was just at the point where every time I'd lose weight I'd gain it back plus a couple more kilograms. It kept creeping up and up to the point where I was huge."
After multiple doctors told Donald she wouldn't be able to lose weight without surgery, she had a gastric bypass at Auckland Weight Loss Surgery.
Before having the surgery Donald was required to go on an Optifast meal-replacement diet to trim fat from her liver and had to run 2km six times a week.
Afterwards, she would have to continue her healthy lifestyle to keep the weight off.
"Just because I've had the surgery, doesn't mean that the weight is just going to fall off," she said.
Donald recommended people undergo the surgery only as a last resort and after they had done lots of research.
Bariatric surgeon Dr Richard Babor said although some gastric bypass patients were able to eat up to three-quarters of a cup of food per meal at 10 weeks post-surgery, others could only stomach a very small amount.
"Most people at that stage would probably be able to tolerate a little bit more food, but it is quite variable.
"[Donald] is doing it rough and many patients do. What I always tell my patients is that pretty much everybody goes through a period where they hate it."
At first some patients wondered if they had made a big mistake, but once they could tolerate more food and started losing weight most were happy.
The perception that bariatric surgery was an easy way to lose weight was wrong, Babor said.
"It sounds so intiutively true. [But] it's just biologically incorrect. For people who have a BMI greater than 35, there's really hardcore scientific evidence that shows that diet and exercise doesn't work."
A recent study by Harvard scientists concluded that kids who were obese should have weight loss surgery.
Babor said he used to disagree with doing bariatric surgery on young people because they generally weren't good at sticking to a healthy lifestyle afterwards.
But after seeing the effects of obesity on kids and teenagers through his work at Counties Manukau DHB he was convinced it could help address New Zealand's obesity epidemic and related health issues like diabetes.
Each year about 400 to 500 bariatric surgeries are publicly funded in New Zealand. However, only a tiny proportion - about 1 to 3 per cent - are performed on people under 25.
Last year treatment for bariatric surgery patients - including pre- and post-operative appointments - cost health authorities an average of $20,519.93 per patient.
Clare Perry, Ministry of Health's group manager of integrated service design, said the Ministry prioritised potential bariatric surgery patients based on their needs and how likely they were to benefit from it before adding them to the waiting list.