The first phase of his three-stage programme, Wellbeing 101, which costs thousands of dollars, involves eating a variety of traditional Chinese herbs.
He says a patient can lose up to 12kg in two weeks.
Liu said it wasn't fasting, as the patient was still receiving nutrition through the herbs - from 70-250 calories.
The primary function of the programme was not weight loss - it was intended to "reset the human body" and cleanse the organs, he said.
"This is to fill the gap between the patients' current health and their optimum health."
The three stages are: clean and release, repair and recover - where massage and acupuncture are used to reset organ function - and whole body recalibration.
But registered dietician at Canterbury Dieticians, Liz Beaglehole, said she wouldn't recommend the programme as a means of weight loss.
"At the end of the day, you're losing weight as you're not consuming anywhere near what your body would need - so it's starving," she said.
"You lose water, then your muscle wastes - particularly on such a low-calorie diet like that, it's completely unsustainable and the risk is that you do all this and your metabolic rate and all your hunger cues get mucked up.
"I just wouldn't recommend that to anyone, you don't know what's going to happen later on. You may end up with all these additional problems that are probably going to lead you to gain weight again."
In an apparent first case of its kind, Liu was prosecuted by the Health Care Complaints Commission in Australia in February and was found guilty of unsatisfactory professional conduct.
The doctor prescribed a programme of fasting, remedial massage and acupuncture for a patient with chronic ulcerative colitis.
Liu said he had appealed the decision and didn't want to talk about the court case. Liu has treated several high profile patients in the past, some of whom he continues to see, although he wouldn't discuss them with The Herald on Sunday due to patient privacy.
However it has been well reported that Liu is credited with helping Australian Prime Minister Malcolm Turnbull lose 14kg in just four weeks.
And Zoe Marshall - wife of Kiwi league legend Benji - adopted Liu's radical diet in her bid to get pregnant.
Liu said he still keeps in contact with Marshall and he showed the Herald on Sunday photos he said she sent him of her new baby. Their son was born earlier this month.
She has written about the programme frequently on her blog.
"It is incredibly hard ... You can't do it for weight loss or a quick fix or you will quit," she wrote.
"It was the most difficult two weeks, the first four days were agony," she wrote.
"But if you can commit you have to give it 100 per cent financially, your time, you need to dedicate yourself to it. Don't question him or cut back on treatments. I don't see Dr Liu at all anymore. But I saw him every day for the first month. And it's not cheap. But it is a life fix and about the same cost as removing my endometriosis."
Marshall attributes her pregnancy largely to Liu.
"We were on the pregnancy programme straight after I finished the three month 101 wellbeing programme and I fell pregnant the second month. So yes I do believe he got me pregnant - Benji did have something to do with it too?"
