Gigi Hadid Blasts Weight Critics Calling Her "Too Skinny" The supermodel hit back at body shamers in a series of tweets. The 22-year-old further explained her fluctuating weight as due to Hashimoto’s disease, which she was diagnosed with at 17. The condition affects the thyroid gland, leading to chronic inflammation. "Please, as social media users & human beings in general, learn to have more empathy for others and know that you never really know the whole story."