Catelynn Lowell learned on Monday night's Teen Mom OG that she was four sizes too big for her wedding dress, and now, she's doing what she can to slim down.

'Teen Mom OG' Stars Attend The 2015 MTV Movie Awards

On Wednesday, the reality star and soon-to-be wife of Tyler Baltierra took to Instagram, where she shared a new photo of her weight loss progress, and revealed to fans that she was beginning waist training.

"Monday's episode of Teen Mom OG brought a lot of attention to Catelynn Lowell's weight struggles, as the episode talked about how she's having issues losing the weight since her pregnancy and wants to get in shape in time for her August wedding to Tyler Baltierra," OK! Magazine reported on Thursday, "And though in the episode it seemed as though Cate was only motivated to get in shape because Tyler made her feel bad about her new figure (tough love!), now Cate is taking matters into her own hands—and starting waist-training!"

Tyler Baltierra Defends His Criticism Of Catelynn Lowell's Weight

A photo posted by Catelynn Lowell (@catelynnmtv) on May 20, 2015 at 2:41pm PDT

Along with the photo above, Lowell told fans, "Thinking about giving this a try! #waistedbykeke @waistedbykeke."

After Lowell received the news of her need to lose weight, her fiance, Tyler Baltierra, suggested she join a gym, and made it a point to stay on her about doing so. In turn, he received backlash online for his allegedly pushy behavior.

In response, Baltierra shared the following tweet with fans:

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