Just three months ago, Jessica Lindsay was gearing up for her second Muay Thai fight.

The 18 year old athlete had been dedicated in her preparation and was focused on making the 64kg weight division.

“Jessica never did anything 50 per cent. When she committed, she committed to it and she would always go beyond,” her family told The Project on Wednesday night.

Then, on a run with her 14 year-old sister Grace the day before the fight, she collapsed.

"Jess was no different to any of us. She was healthy. She was training hard right up to the point she passed out," Grace said.

"We had no signs. She was healthy a week before. She was healthy five days before that happened."

She didn't regain consciousness and died in hospital four days later.

In order to make the weight division, the Perth teenager had employed 'weight-cutting', a practice reportedly common amongst wrestling, boxing and mixed martial arts. It's a way to temporarily lose (or gain) weight fast, often by loading up your body with water, fasting, vomiting, excessive exercise or sauna use.

In Jessica's case, she had been wearing a rubber jacket during workouts in warm weather to shed kilograms faster. The strain it put on her body meant her organs started to shut down.

Her family has been left devastated.

"I apologise all the time. I am so sorry to my baby because I should have been there to protect her. I couldn't protect her if I didn't know either," mum Sharron told The Project.

"I want everyone to be educated and aware that this isn't acceptable anymore."

Champion kickboxer Daniel Dawson, who has experienced the dangers of weight cutting first hand, told The Project the process needs to change.

"There will always be fights and weight divisions. That won't change. How we do that, the process, that is what I want to see changed."

Image: The Project

The risks of weight cutting are no secret. Scottish-born 20 year old Muay Thai boxer Jordan Coe died of a suspected heatstroke last year in Thailand as a result of trying to make weight.

There were also calls for the UFC to do something about the practice in December last year after a number of fighters were admitted to hospital or concerned about their health in the lead up to weigh ins.

While exactly how it will be legislated is unclear, it's certain a culture shift is needed.

"Everyone who does this sport is at risk. No family should have to go through this and every mother shouldn't have to have this fight whilst screaming for their daughter or son," Sharron said.