The model took to Instagram to reveal shocking facts about her condition.
Photograph: Regis Duvignau/Reuters
Model Gigi Hadid revealed on social media that she suffers from Hashimoto's disease, a thyroid condition that has contributed to her fluctuating weight over the past few years.
'For those of you so determined to come up with why my body has changed over the years, you may not know that when I started at 17, I was not yet diagnosed with Hashimoto's disease; those of you who called me 'too big for the industry' were seeing inflammation and water retention due to that,' she revealed.
'Over the last few years I've been properly medicated to help symptoms including those, as well as extreme fatigue, metabolism issues, body's ability to retain heat, etc.
The model said that she was also part of a holistic medical trial that helped balance out her thyroid levels.
'Although stress and excessive travel can also affect the body, I have always eaten the same, my body just handles it differently now that my health is better,' she added.
'I may be 'too skinny' for u, honestly this skinny isn't what I want to be, but I feel healthier internally.
'I will not further explain the way my body looks, just as anyone, with a body type that doesn't suit your 'beauty' expectation, shouldn't have to.
'Not to judge others, but drugs are not my thing. Stop putting me in that box just because you don't understand the way my body has matured,' Hadid wrote.
'Please, as social media users and human beings in general, learn to have more empathy for others and know that you never really know the whole story.
'Use your energy to lift those that you admire rather than be cruel to those you don't.'
The model later told E! News on the sidelines of the New York Fashion Week the reason why she chose to come forward with her story now.
'I think it's good to be honest. I've talked about my experience with Hashimoto's, but a lot of people can connect with it.
'I've loved my body when I was just diagnosed and I loved (it) going through it and I love my body now.
'It's just about everyone accepting their body as it matures and knowing that it's not always going to look the same and you can love yourself in all different sizes,' Hadid said.
According to WebMD, the disease that Hadid is suffering from is an autoimmune disease, which is also known as chronic lymphocytic thyroiditis.
The condition is an autoimmune disorder in which the immune system turns against the body's own tissues.
The immune system then attacks the thyroid gland leading to chronic inflammation.
Causes and symptoms
While the exact causes of the disease are unknown, research says that it could be genetic. Mild at first, the symptoms may take years to develop.
The following are some of the symptoms of Hashimoto's disease: