Queensland doctor's fasting diet gets results

A weight loss program developed by a Queensland doctor is making a huge difference to the lives of patients.

One has seen a dramatic improvement in his blood pressure and diabetes and he's lost 30 kilograms without paying a cent or stepping foot into a gym.

Just over a year ago, the simple task of tying shoelaces was impossible for Malcolm Simmonds.

"I was so overweight that I was obese," he told 9NEWS.

"I was about 111kgs."

His secret is a little-known lifestyle called the Nysteia Formula.

"Nysteia is a novel approach to weight loss," Dr Andrew Renaut, from Brisbane Surgeon said.

"The Greeks were the first people to appreciate the benefits of fasting 3000 years ago."

There are three main rules: Intermittent fasting; eating a Mediterranean-type diet; and cardiovascular exercise - but it can work without this, too.

"Yes, you can do it (leave out the exercise), but it's just going to take longer to achieve your goals," Dr Renaut said.

While following the Nysteia Formula, people only eat within a six-hour window during the day, then fast for 18 hours.

The idea is the body will produce less insulin, allowing it to use stored fat as energy.

Cancer surgeon Dr Renaut became an advocate after seeing so many patients fail on traditional diets.

"The calorie-restricted diet has been shown to fail time and time again," Dr Renaut said.

"That's because it doesn't address the underlying issue, which is insulin resistance."

There's no set rule about when to eat and fast. But it's recommended people stick to the same routine each day. Unlimited amounts of water, black coffee and green tea are allowed during fasting hours.

"I think it will work for anybody who wants to achieve their ideal weight," Dr Renaut said.

Mr Simmonds' new lifestyle means he's now off medication for high blood pressure and diabetes.

"The biggest difference with me is enjoying yourself a little bit more because you're so much more active," Mr Simmonds said.

"When you've got grandchildren, you need the energy, believe me."