Before stripping down for the 2015 Sports Illustrated Swimsuit issue, Rousey gained 15 lbs. to feel her "most attractive"

Credit: Mark J. Terrill/AP

When UFC fighter Ronda Rousey, 28, signed on to pose for the Sports Illustrated Swimsuit Edition 2015, she wanted to be at her most beautiful – and that meant gaining weight.

“I felt like I was much too small for a magazine that is supposed to be celebrating the epitome of a woman. I wanted to be at my most feminine shape, and I don’t feel my most attractive at 135 lbs., which is the weight I fight at,” Rousey told “At 150 lbs., I feel like I’m at my healthiest and my strongest and my most beautiful.”

The undefeated UFC Women’s Bantamweight Champion – who’s always popping up in movies like Entourage, Expendables 3 and Furious 7 – grew up practicing judo, so her body was never “conventional.”

“I grew up thinking that because my body type was uncommon [i.e., athletic], it was a bad thing,” she told Cosmo. “Now that I’m older, I’ve really begun to realize that my body has developed for a purpose and not just to be looked at.”

Rousey admits that it took her a long time to develop a healthy relationship with food and her weight. “My mind was backward. I thought I wanted my body to look a certain way so I could be happy,” she said.

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Rousey said she finally figured out how to balance the weight requirements of her job with her own well-being – and with that discovery came happiness.

“Now I only try to maintain my fighting weight for a couple hours a year – right before weigh-ins. Afterward, I maintain a weight where I’m not starving or feeling weak, which makes me happier.”