A YouTube star who claimed a vegan lifestyle cured her breast cancer has died of cancer.

Mari Lopez, who was known for blogging alongside her niece, Liz Johnson, as Mari & Liz, died from the disease in December, according to Liz - after it spread to her blood, liver, and lungs.

However, Liz claims veganism could have saved her aunt - despite the spread of the disease - if only her carer hadn’t fed her meat.

On their YouTube channel, where Liz and Mari had 11,761 subscribers, they posted videos in which they promote a vegan lifestyle and faith in God - and discuss how both healed Mari's cancer.

In one video, titled: "Cancer Transformation FAQ," Mari said: "The lemon-ginger blast helped me remove inflammation from my body," but that she did suffer from "food withdrawals" when going through a 90-day juice cleanse.

"It felt horrible and it was like I was catching the flu," Mari recalled of incorporating detox teas into her 90-day juice cleanse regime, but said the detoxes were "washing my body."

Mari also revealed that she completely skipped cancer treatment as recommended by her doctors.

"It's my choice, I've been okay, I haven't died, I haven't gotten to the hospital... I am going to continue on this path of going natural," Mari said at the time, "It's over, it is done with, I am healed. I feel it in my spirit and in my body."

In another video, titled "Stage 4 Cancer Natural Transformation," Mari revealed how God drew her to the fruits and vegetables in the grocery store that would cure her.

When she died Mari was following a vegan lifestyle, as promoted on their YouTube channel, but "wasn't completely consistent with what she had said in the video," according to Liz.

“My family is not familiar with that style of living… What happened was, as Mari was living with my mom, my mom started to tell her that she needed to eat meat now,” Liz told Babe.

This, Liz claims, coupled with the use of a microwave to cook the food, is what ultimately led to her aunt’s demise.

Liz and Mari discuss their vegan lifestyle and Mari's cancer healing (YouTube)

“My aunt was very against the microwave because of cancer-causing issues with that, and my mom would cook her things using the microwave,” Liz told Babe.

According to Cancer.org, when microwave ovens are used according to instructions, there is no evidence that they pose a health risk to people.

And any injuries associated with microwaves are most often burns resulting from contact with steam or hot food.

However, Liz is adamant that the microwave and the meat were her aunt’s downfall - a belief that her aunt no longer shared towards the end of her life.

According to Liz, Mari asked her to remove the YouTube videos where she hails veganism as a cure for cancer when she realised she was going to die from the breast cancer, but Liz refused - because Liz still believes in the power of veganism.

Liz has revealed her aunt has died from the cancer (YouTube)

Since her aunt’s death, Liz has disabled the comments section on her YouTube channel - and released a new video, titled “The Truth about Mari - CANCER, JUICING, & FAITH,” in which she discusses Mari’s passing, and states the pair were not trying to mislead people but “genuinely trying to help.”

And Mari insists this has not been about money - as her and her family "received just pennies" from the advertising on YouTube.