Courtesy of Armani

We're not really sure how much empathy this one warrants!

While Megan Fox looks quite thin in her racy ad campaign for Armani, her trainer, Harley Pasternak, assures that the sexy star definitely doesn't have an eating disorder. In an interview with, Pasternak reveals that the "Jennifer's Body" actress really struggles with gaining weight.

"Do I worry about Megan getting too skinny? Yeah!" Pasternak said. "Believe it or not she has this really fast metabolism," Pasternak continued. "So her training is all about body toning and sculpting. With her its really about she's eating enough of the right things. People thought, 'Oh she must be anorexic,' but she's far from that!"

gets upset when people question whether or not she's anorexic. "She gets frustrated at times because she's like 'I need to put on weight.' So she actually weight-trains to keep on that lean muscle tissue," he said.

Pasternak, who also trains Robert Pattinson, Katy Perry and Amanda Seyfried, then described the kind of training he does with Fox that results in her toned abs. "The key to Megan's abs is first of all genetics," Pasternak admitted.

"The second is that we train her abs on all three planes. It's not just about crunch, crunch, crunch. It's about working her body up and down and side to side and rotation. We train all three of her rectus abdominis, her obliques and her corset muscle to make sure that her abs are not just tight and strong but small. The corset pulls it all in," he concluded.

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And don't miss Fox starring alongside Tennis ace Rafael Nadal for Emporio Armani Underwear and Armani Jeans: