Despite Kourtney Kardashian's embrace of her curvier figure, sources say her sisters Kim and Khloé are concerned that she is losing control of her body image.

Insiders suggest that Kourtney's diet and exercise routine have taken a back seat to her romance with Blink-182 drummer Travis Barker, causing her siblings to worry, according to National Enquirer.

"Kim and Khloé are saying it's shocking she's piling on the pounds and blaming Travis for leading her into this lazy, gluttonous new lifestyle," reveals an insider.

The 44-year-old mother of three, who is happily married and has children from her previous relationship with Scott Disick, recently shared photos on social media of her bathroom filled with plates of food.

Sources say that her sisters were appalled by the display. "They're appalled at the way Kourtney's eating takeout like it's going out of style," shares the insider.

"Kourtney and Travis clearly enjoy their food as much as they enjoy their obviously red-hot sex life. But it's too much for Kim and Khloé, who are proud to starve themselves six days out of the week and work out ferociously to look super slim!" adds the source.

Despite the criticism, Kourtney, who has admitted to having a "thicker body" after undergoing IVF treatments, is reportedly enjoying her favorite meals in moderation. However, insiders say she has reduced her gym routine and steered clear of liposuction and other artificial enhancements since her wedding last year.