A vegan YouTube star who claimed her plant-based diet 'cured' her cancer and lesbianism has died from the disease.

Mari Lopez, who ran the food channel at home in Houston, Texas with her niece Liz Johnson, told thousands of viewers she had rejected traditional treatment for breast cancer in favor of a 90-day juice cleanse when she was diagnosed in 2015.

Within four months of cutting out animal products, she claimed to be in remission - and insisted the new regime (and God) had 'healed' her of her 'gay lifestyle'.

But Liz has now revealed that her aunt passed away in December 2017, after the disease spread to her blood, liver and lungs, and belated attempts to try chemotherapy and radiotherapy failed.

Speaking to Babe, Liz blamed her own mother for triggering Mari's relapse by feeding her meat and microwaved food.

There is no scientific evidence to support Liz's claims.

Mari Lopez (right) has died of cancer two years after claiming a juice cleanse had cured her of the disease. Her niece and co-host Liz Johnson (left) claims she wouldn't have died if she had stayed vegan and refused treatment when she relapsed. There is no science to support that

'Mari was living with my mom, my mom started to tell her that she needed to eat meat now,' Liz told the site last week.

'My mom would buy her burgers and things like that, and she didn't want to eat that but after a while she just was just OK with it.

'When you give in too many times, you just end up saying whatever. I feel like that's what caused the issues.'

She added: 'My aunt was very against the microwave because of cancer-causing issues with that, and my mom would cook her things using the microwave.'

As her health worsened, Mari asked Liz to take down the videos, which had titles like 'stage 4 cancer healed by juicing' and a juice recipe called 'the cancer killer'.

Liz, however, refused, saying she believed that her aunt would have survived if she had stuck to her juice-based diet.

'I still agree with the message, completely,' she said. 'I would agree with it and I still go behind that message. You have your spiritual side and your physical side that work together to improve you as a whole. That's the message.'

Mari told viewers her juicing lifestyle and faith in God cured her of cancer and lesbianism

The duo would make juices and call them 'cancer killer' on videos watched by thousands

She has since updated videos with a message, informing viewers that her aunt has died of cancer after making said cancer-killing juice, and as such asks them to keep negative comments to themselves.

The videos still amass up to a million views.

In them, Mari declares: 'I was healed by God and faith and used to live a gay lifestyle.'

Since announcing Mari's death, Liz has posted a video in response to the slew of backlash, insisting she stands by their claims.

'My aunt was inconsistent in her diet and spiritual life,' Liz says.

'She did not continue juicing/raw vegan diet when she got diagnosed again, she chose to do radiation and chemo.

Mari passed away in December 2017, after the disease spread to her blood, liver and lungs, and belated attempts to try chemotherapy and radiotherapy failed

Liz told viewers her aunt was inconsistent in her juicing and faith, and blamed her own mother for feeding Mari meat and microwaved meals

'I never pushed my aunt to do anything or stay away from doctors.

'She chose to do what she did and experienced healing, leading her to share her testimony to help others.

'I have never been against doctors or medical advice. I never claimed to heal my aunt's gay lifestyle through juicing.

'My aunt chose to make that change on her own, which had nothing to do with her juicing but everything to do with her faith.'

While scientists have spent decades and billions of dollars on countless studies into food and cancer, there remains no 'magic bullet' diet to prevent the mysterious disease.

Though many studies have shown the Western diet - of processed foods and sugar and few vegetables - has tumor-feeding properties, many people have lived a long life disease-free on a diet of hamburgers and fries.

Oncologists warn it is misleading to present any diet as a sure-fire cure, and the misconception that it can stems from people misrepresenting scientific findings.

'In some sense, oncologists view nutrition as alternative medicine,' Lawrence H. Kushi, ScD, associate director for Etiology and Prevention Research at the Kaiser Permanente Northern California Division of Research, Oakland, California, told Healio.

'To the extent nutrition is thought about by most clinicians, it has been in the context of ensuring patients receive enough calories so they can withstand the toxic effects of treatment.'