Despite photos of Megan Fox that show the actress becoming increasingly thin, Fox’s personal trainer says she just has a “really fast metabolism” and has a hard time gaining weight.

Reports Hollywood Life:

“Do I worry about Megan getting too skinny? Yeah!” exclaims Harley, who trains Megan and other celebrities like Robert Pattinson, Katy Perry and Amanda Seyfried.

“Believe it or not she has this really fast metabolism,” explains Harley. “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!”

In fact, Harley reveals, Megan gets very upset when she hears people think she has an eating disorder, especially since she struggles to gain weight. “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.”

Ah, the “really fast metabolism” explanation. You know that always makes those of us who gain weight just by smelling a cupcake feel soooo bad for you!

Do you think Megan’s problem is really her metabolism?