‘This Is Us’ Spoilers: Toby’s Secret Weight Loss Could Mark Trouble For His Marriage To Kate

Spoiler alert: This article contains mild spoilers for This Is Us Season 4.

This Is Us fans know that Kate and Toby (Chrissy Metz, Chris Sullivan) have had a difficult relationship from the get-go, but things could take an even trickier turn for them now that Toby is focused on fitness behind his wife’s back.

On the most recent episode of the NBC drama, Toby’s weight loss was apparent as he used CrossFit gym workouts as a coping mechanism to deal with the stress of his prematurely born son Jack’s medical problems. Toby has been lying about his frequent gym trips to Kate and blaming his slimmer physique on the stress of being a new father to the permanently blind baby.

In a new interview with People, Sullivan, whose character suffered a heart attack in Season 1 explained, “As of right now, it seems like Toby’s figured out where his priorities are, and his priorities are staying alive as long as possible for his son.”

But Metz, whose Kate character has turned to overeating as she copes with the stress of motherhood, teased that Toby’s secret-keeping could spark trouble for the new parents.

“I don’t think that fans will necessarily expect the secrets that Toby was keeping and how that’ll affect their relationship and moving forward. There’s a bit of trust that’s broken in him keeping this weight loss and working out a secret.”

This Is Us executive producer Isaac Aptaker told Entertainment Weekly that Toby’s motives date back to that serious heart incident in Season 1 and the fact that he wants to “be on this planet as long as possible” for his special-needs son. Aptaker added that Toby is keeping his gym routine “on the DL and flying under the radar” instead of flaunting it in Kate’s face because he’s trying to “protect” his wife, who is breastfeeding and not in a place where she can go on a strict weight-loss plan.

“Certainly, Kate is aware that he’s smaller, but she doesn’t know the extent he’s going to [in order] to lose the weight,” the This Is Us boss said.

Aptaker also teased that Toby’s outlet for his anxiety could prove to be detrimental to his already stressful marriage.

“Toby has found this path that’s working for him, and because he doesn’t want to rub it in her face he’s making the choice to keep it a secret. That’s dangerous in any relationship, keeping secrets like that.”

In a preview for the upcoming This Is Us episode, “Unhinged,” Toby finally appears shirtless to show off his buff bod to Kate. In the clip, which you can see below, a housebound Kate seems blindsided by her husband’s weight loss and not exactly happy, so this may not bode well for the two.

In real life, Chris Sullivan was never the same size as his character Toby. Us Weekly previously reported that Sullivan initially wore a fat suit and prosthetic jowls to play the role of Kate Pearson’s love interest.

This Is Us airs Tuesdays at 9 p.m. on NBC.