Katherine Webb is fighting back against critics who claim she is "too skinny."

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According to a new report, the model wife of NFL quarterback AJ McCarron was recently targeted with mean-spirited comments online. In response, Webb shared a heartfelt message on Instagram, revealing to fans that she has been suffering from a thyroid condition.

"To all of you who think I need to gain weight or eat more, I eat just fine," Webb wrote on Tuesday. "I am 5'11 so I have a lot more places to put my calories. I eat crap most of the time anyways."

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Webb first gained fame in 2012, when she was named as Miss Alabama 2012. Then, in 2013, she received national attention after attending the 2013 BCS National Championship Game. During the game, commentator Brent Musburger noticed Webb in the audience, and told viewers she was a "lovely lady" and "beautiful."

One year later, Webb married McCarron, whom she had been dating for four weeks when the game aired.

"To all the middle-aged women who like to leave mean comments on my page about my body, you can gladly skip my page and go somewhere else," Webb continued. "I am tall, I eat just fine and also suffer from thyroid problems so don't make fun of me or my body when you probably have problems of your own. I rarely react to this kind of stuff, but this really bothers me."