As we well know, the phrase "body image" functions like a four-letter word within the fashion industry. Everyone has a different ideal... and everyone has a different theory about where it came from. At last, we have evidence of the perfect body's origins.

Tracy Anderson, whose official title is "fitness entrepreneur" according to Into the Gloss, explained her exercise method's origins on their site today. The trainer is famous for carving high-profile celebrities' bodies, like Madonna's, Gwyneth Paltrow's, Jennifer Aniston's and Kim Kardashian's, into enviably svelte shapes. But there was one butt in particular that inspired Anderson's rise... and it belongs to Gisele Bündchen.

Tracy explains that she turned to the glossies in search of a perfectly proportioned body to idealize:

"I had to think: whose butt do I think everybody wants? And before Gisele was even a household name, I cut her butt out of a Victoria's Secret catalogue, and I was like, 'I think every woman wants that butt.' And then I went through magazines and things, trying to find examples for the rest of the body, thinking, 'These arms look too bulky. These arms look too scrawny and lifeless. I feel like women want this leg, women don't really want a six pack on their abs, but they want their stomachs to curve in and then curve out.' I literally had to work out what I thought every woman wanted. But the only piece that I took from an actual person was Gisele's butt. I laugh about it now, but everybody still wants that butt. She's pretty timeless."

Two things to glean from Anderson's hunt: 1) No one woman has the complete perfect body and 2) Gisele's butt is timeless and perfect. Tracy's biggest fan, Gwyneth Paltrow, famously professed to possessing "the butt of a 22-year-old stripper" after converting to Tracy's practices; logically, this must mean Gisele has the butt of a 22-year-old stripper, too.

As Anderson influences the most obsessed-over celebrity bodies, and Gisele influences Anderson's techniques, it seems the whole world inadvertently aspires to look like Gisele. Or her perfect posterior, at least. Do you think there are any ifs, ands or, uh, butts to our argument?

The butt that launched a thousand treadmills:

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  • H&M Fall/Winter 2013

  • BLK DNM, Spring 2013

  • Chanel, Spring 2013

  • Versace, Spring/Summer 2012

  • Dolce & Gabbana

  • Versace Jeans Spring 2012

  • Givenchy S/S 2012

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  • Esprit, F/W 2011

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  • Isabel Marant S/S 2011

  • Versace, 2009

  • Calzedonia, Summer 2010

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  • Roberto Cavalli, Fall 2010

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  • Versace F/W 2010

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  • Dior S/S 2009

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  • True Religion S/S 2009

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  • Loewe, Fall 2009

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  • Max, 2009

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  • London Fog, 2009

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  • Stefanel S/S 2008

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  • Ebel, 2008

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  • YSL, Fall 2007

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  • Louis Vuitton S/S 2006

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  • Salvatore Ferragamo Spring 2012

  • Dior S/S 2003

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  • Givenchy Eyewear, Spring 2012

  • Ipanema

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  • H&M, Spring 2011

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  • Valentino

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  • Missoni

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