The chorus has grown louder since new photos of her were posted on the Ford Models blog on June 30. In the pictures, Renn, with sunken eyes and hollowed cheeks, is wearing a T-shirt that barely skims the tops of her noticeably thinner thighs.
Michael Gross, author of "Model: The Ugly Business of Beautiful Women," thinks Renn is "fair game" for the criticism she's receiving.
"She has cashed in on gaining weight and now she's losing weight," he told ABCNews.com. "I don't know whether it's hypocrisy...but it's worth making an observation about."
Again, Dakin defends his client. "She knows how to move, and she can angle herself to whatever position," he told the New York Post recently. "She knows how to work lighting. I understand that in the picture she looks smaller, but I also understand that the industry does things that can make models appear differently. Crystal ranges between a 10 and 12, but she's never not been a 10."
Renn's friend and fellow plus-size model Kate Dillon thinks Renn may be a bit smaller. "She looks like a size 8, 10. She's definitely not a size 4 or 2," Dillon told the Post. "I know she loves herself now. She went on a big hiking trip, and she had a physical awakening as to how good it feels."
Crystal Renn's Downsizing Sign of Trouble?
Even though plus-size models can allow their weight to fluctuate more than other models, Renn's shrinking size is seen as a troubling sign to some.
After all, here is a woman who literally risked her life to conform to the modeling industry's standards for thinness.
At 16, Renn moved to New York City from her hometown in Mississippi, signed a $250,000 modeling contract and spent up to eight hours a day at the gym and starved herself.
"Even though I was accomplishing my dream, I was absolutely miserable," she told Robin Roberts on "Good Morning America" last year.
At 5 feet 9 inches and 95 pounds, Renn was told she still wasn't thin enough.
"I knew that no matter what I did … I'll never be good enough to meet the weight standard of a traditional fashion model," she said. "And I might lose my dream."
Instead, as Renn chronicled in her book "Hungry," she began eating again and decided at age 18 to become a plus-size model.
"My life and everything about me finally flourished," she said, once she began accepting her body.
Renn, who had graced magazine covers, including four international editions of Vogue, and walked in runway shows for top designers such as Jean-Paul Gaultier, is now one of the most successful plus-size models working today.
So it is ironic that at the top of her game, Renn appears to be getting thin again.
She's certainly not the first female celebrity to slim down as her popularity rises. Hollywood actresses like Nicole Kidman and Renee Zellweger are thinner than when they first became celebrities. Singer-actress Jennifer Hudson is the latest star to downsize with fame. The new spokeswoman for Weight Watchers, she made the cover of People magazine proclaiming, "My New Body. WOW! Size 16 to Size 6!"
How Renn's weight loss will affect her career remains to be seen.
"It just depends if she will keep clients with the fluctuation in size or if she is choosing to stay smaller than when she came out on the scene," Emme said. "Really it's an internal decision for her career between her and her agent."
Her fans will be waiting to see what she decides.