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Two-time Sports Illustrated cover girl Kate Upton upended the modeling world in 2012, bringing back curves, scoring lucrative high-end contracts with the likes of Mercedes Benz, and even infiltrating the high-fashion pages of Vogue.

But if the latest string of international fashion weeks is anything to go by, Upton may be an anomaly, as skin-and-bone bodies ruled the runways. Despite the outcry in recent years to curb using excessively waif-like models on the runway, and the establishment of organizations such as the non-profit Council of Fashion Designers of America (CFDA), curves were nowhere to be seen in New York, Milan, London or Paris.

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“[The models are] as skinny as they have been in years before,” one fashion week observer told FOX411’s Pop Tarts column. “If not thinner.”

According to high fashion model Kira Dikhtyar, “decisions regarding what models to use are still made by the same five to seven casting directors, who are choosing skeletal-like girls who actually kind of look the same.”

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“The clothing samples for the shows are size zero. If they cast someone over that, they won’t fit the collection,” she explained. “Kate Upton made it not as a fashion model, but as a celebrity. Designers will not go against the size zero rules, that is why we don’t see Kate or any other curvy girls on international runways.”

And the super skinny aesthetic isn’t limited to females either. A shockingly gaunt and ill-looking male model appearing in the Yves Saint Laurent men’s show at Paris Fashion Week ignited fears of “manorexia” – a word twist on the dangerous eating disorder anorexia – prompting fashion bloggers and observers to voice their surprise and disappointment.

“It is not that the designers of 2013 are flying in the face of the recent fashion pact, they are merely trying to sell their clothes. Fashion is in a volatile time of change, and designers are trying to present their clothes to the widest possible audience,” insisted prominent stylist, David Zyla. “Therefore, by showing fashion on women who do not have a full bosom or curvy hip, the audience is not distracted by the wearer and the clothing stands out. What this translates to, however, is hiring a body type that happens to be super skinny.”

But not everyone agrees that clothes sell better on a fragile figure.

“It’s an absolute outrage that we have to watch skinny girls wasting away. We always hear the argument that clothes ‘hang’ best on skinny models, but women want dresses to flaunt their bodies not ‘hang’ on their bodies,” argued New York-based model publicist, Nadja Atwal, who was recently named ‘Sexiest Power Woman’ of all-time by Viva Glam Magazine. “These designers are in for a rude awakening. I predict there will be a whole new army of models with Upton-curves, we need ‘healthy’ and ‘sexy’ back.”

Indeed some of the world’s top models contend that the Kate Upton-esque curves are still very much in demand.

“In Europe I saw some of my friends who are models who did those shows who are curvy. I didn’t follow Fashion Week too much but I did my friends doing the shows and they were curvy. I was happy for them,” Victoria’s Secret Angel Alessandra Ambrosio told us at last week’s SWIM launch in Los Angeles. “Personally, I am all about the curve.”

Fellow VS superstar Candace Swanepoel, who came under fire for an apparent dramatic weight loss two years ago, said that she too is all for the more voluptuous woman, embodied by 90s supermodels like Cindy Crawford.

“It’s not really about who is skinny and who is not, a lot of those girls are like, 13 years old, so they are naturally skinny,” she said. “I was the same. There is that whole buzz about it, but I think healthy whatever body type you have is important.”

Meanwhile, high fashion’s model of the moment, Karlie Kloss, noted that designers simply show their collections depending on what they think best suits their collection.

“But as a model and individual you have to embrace your own body type, regardless of the runway trends,” she said. “Curvy is not going anywhere. The world definitely likes booty.”

Atwal also pointed out that the models themselves, and not just designers, need to be held accountable to the ongoing dangerously emaciated fad.

“Skinny models might get a gig on the runway, but it is the curvy models like Kate Upton and Heidi Klum that become stars and make the big bucks. We have to remind ourselves that no one puts a gun to a model’s head and says ‘be a skinny model.’ Every girl can decide to resist their agent’s demand to lose weight or simply quit the business and pursue another career,” she continued. “I know many models who said no to losing weight and they have great careers today.”

One such success story is model Brittany Binger, who claims that a little weight gain actually brought more casting calls and contracts.

“Designers have always liked models on the thinner side. Is being that skinny anymore for me? No,” she said. “I am happy with the weight I have gained. You can still have a successful modeling career without being ‘too skinny.’”

The CFDA did not respond to a request for comment.

Danielle Jones-Wesley contributed to this report.