Everyone faces a battle no one knows about.
For Gigi Hadid, that's thyroid disease.
The 21-year-old may grace our magazine covers and walk down every runway, but because of her Hashimoto's disease she's unable to keep weight on — which can be tough, even for a supermodel.
"My metabolism actually changed like crazy this year. I have Hashimoto's disease. It's a thyroid disease, and it's now been two years since taking the medication for it, so for the VS show I didn't want to lose any more weight, I just want to have muscles in the right place, and if my butt can get a little perkier, then that's good."
Miz Hadid went on to chat about maintaining her weight through her diet: