Once inside the gym, Khloe took a selfie and admitted to recently gaining weight.
But according to the reportedly now-single star -- she reportedly just broke up with rapper French Montana -- she's not the only one to blame for the extra pounds!
"Monday with @gunnarfitness!!! I am determined to get my pre-hamptons, pre- sympathy kourtney pregnancy weight off. Nothing good comes easy. Why do I blame Kourt though?!? Lol," she wrote on Instagram Monday.
Though Khloe isn't the only Kardashian looking to lose weight.
Rob Kardashian, 27, addressed his now fuller figure in May, which shocked fans when he was photographed at the airport on the way to Kim Kardashian and Kanye West's wedding.
"First, I don't believe in rehab or therapy or anything of that sort and second I'm a grown man and will work on myself when I choose," he tweeted on May 20. "I'm aware that I'm fat that def aint a surprise to me lol and my only therapy will be in the gym anyways had to say somethingggggggggg."