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.
The number of young New Zealand 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.
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 track.
Despite being frustrated by its side effects, Donald didn't regret having the surgery.
"It's changed my life," she said.
Before her surgery Donald weighed 126.5 kilograms and had a body-mass index 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 kg. It kept creeping up and up to the point where I was huge."
After doctors told her she wouldn't be able to lose weight without surgery, she decided to have a gastric bypass privately in Auckland.
Donald said she hoped sharing her story would show people weight loss surgery wasn't "the easy option".
"Just because I've had the surgery, doesn't mean that the weight is just going to fall off."
She didn't know anyone else her age who had had a gastric bypass and would only recommend surgery as a last resort.
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 the stage would probably be able to tolerate a little bit more food, but it is quite variable."
He said Donald was doing it rough as many patients did. "What I always tell my patients is that pretty much everybody goes through a period where they hate it."
At first some patients even 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.
But he added : "For people who have a BMI greater than 35, there's scientific evidence that diet and exercise doesn't work."
A recent study by Harvard scientists concluded that kids who were obese should have weight loss surgery.
Each year about 400 to 500 bariatric surgeries are publicly funded in New Zealand. Last year bariatric surgery — including pre- and post-operative appointments — cost health authorities an average of $20,519.93 per patient.
