TLC’s docuseries My 600-lb Life has chronicled the lives of dozens of people looking to lose weight. As far as we can recall, though, few of the show’s subjects have endured as many hardships as Liz Evans — as you’ll see in the Jan. 31 episode.

“Liz is completely bed-bound with severe lymphedema that makes it impossible to walk,” TLC says in a press release. “Utterly isolated, with no friends, she battles depression and [lives] with her mom, who is too ill to take care of her. Liz desperately wants to become mobile.”

The first part of the episode is already streaming on Vimeo, so we know a little bit more about Liz’s backstory. “When I was a little girl, I was a normal size, but I was born with an abnormality in my leg,” she explains. “The bone was curved, which resulted in one leg being shorter than the other. I walked but I walked with a little limp, so I couldn’t be as active as I would have wanted to be.”

Still, Liz says she had a relatively normal and happy childhood until she was molested at the age of six “by someone [her] family knew.” Things only got worse from there when her father succumbed to an addiction and withdrew from family life. By the age of 10, Liz had turned to food to distract herself. “As things got harder, I just ate more,” she shares.

At the age of 11, Liz underwent seven corrective surgeries on her leg. “While I was recovering from each of these surgeries, I had to stay in bed all day, so that’s when I started to really gain. And by the time I turned 13, I was over 250 pounds.”

By 24, she had crossed the 400-pound mark. “That’s when I started developing lymphedema on my legs. That started making it even harder to get around. And that’s when my weight really spiraled out of control,” she reveals. Lymphedema is often caused by damage to the lymph nodes, organs that are part of the body’s circulatory and immune systems. There is no known cure, but according to The Mayo Clinic, the condition “can be managed with early diagnosis and diligent care of [the] affected limb.”

liz evans my 600-lb life tlc

When Liz was 25, her mother got sick with double pneumonia and mini-strokes, and she never fully recovered. Eight years later, her father died. By that point, Liz’s lymphedema had gotten so bad that she couldn’t attend his funeral. “I was not able to physically be there at least to just lean over, hug him, or touch his face, or kiss him, or something. And ever since then, it just was downhill, and I’ve been stuck in this bed,” she says.

Liz’s mother tells TLC she’s terrified by the prospect of her only child predeceasing her, and Liz knows her situation is critical. “I have to find someone to help me stop this and to change, or my worst fears are about to happen,” she admits.

Can Liz get the help she needs? Tune in tonight, Jan. 31, at 8 p.m. EST on TLC.