The plus-sized character on 'This Is Us' has one major problem — and it's not her weight

“This is Us” has the potential to be NBC’s new “Parenthood”: A show centered on a tight-knit family who will likely make you cry at the end of every episode. The series, which premiered Tuesday (September 20), is getting a lot of buzz right now for for featuring “Gilmore Girls” alum Milo Ventimiglia — and his naked butt — and a tear-jerking plot twist. The pilot is also worth watching for "American Horror Story" alum Chrissy Metz, who plays Kate on the show.

We learn two things about Kate in the first episode: 1) That she has a very handsome twin brother named Jack who’s an actor and 2) Kate is unhappy because she is struggling with her weight.

As wonderful as it is to have a plus-sized woman as a main character on a show, it’s disheartening to see what defines her (at least in the pilot) is her weight. In fact, while we get a sense of the professional lives of her brother (Justin Hartley) and another central character named Randall (Sterling K. Brown), Kate is only seen confronting her self-loathing, first with a fridge full of notes ordering her not to eat any food, and then at a weight loss support group where she tells a fellow member she can’t date him because she doesn’t want to date another fat person.

Even with the success of "Roseanne" in the '90s and Melissa McCarthy's recently-concluded sitcom “Mike & Molly,” it’s still all too rare to see a plus-sized woman with a starring role on a network series. So it feels like a letdown that when we finally do get a person like Kate on TV series, every other line out of her mouth is either about how much she doesn’t like being fat and how determined she is to lose the weight.

Here’s the thing about TV pilots: The show’s writers have to do a lot of work in setting up the characters and storylines, which often means that the characters tend to be one-dimensional rather than fully fleshed out people. So perhaps we can give “This is Us” a pass for only giving Kate one defining characteristic and a love interest who calls himself the “fat friend.” But while it’s wonderful to see a plus-sized main character on TV, it would be downright revolutionary if Kate’s journey wasn’t about losing the weight, but about learning to love herself for who she is and embrace body positivity.

Because if Kate only sees herself as fat, that means the show’s viewers will only view herself that way too, rather than as an interesting, multidimensional person who has more going on than her fear of standing on a scale.

In an interview with “The Real,” Metz talked about representing plus-sized women on television, noting that she’s had her own struggles with weight since she was age three.

“So many people feel as if they’re defined by a number, whether it’s a salary or a number on the scale,” she said. “And we’re so much more than that.”

Let’s hope that her show’s writers heed Metz’s words and do not limit her character to simply her relationship with number on a scale. Even if Kate comes across as less than dimensional, she and Metz are already resonating with fans in a major way.