The New Yorker regularly posts videos and articles about relatable issues like dating and mental health, but what’s he’s best known for is his advocacy of self love at any size — a topic he understands intimately.
In 2009, Diaz was 16 years old and weighed around 225 kilograms. He took part in a study at New York University Medical Centre, examining how lap band surgery impacted young men and women.
The scope of this transformation is insane, and I’ll never try and act like it isn’t. In 2009 I was more than double my current weight. I was unhealthy, insecure and I had a lot of problems. But at the same time, I’m not going to demonize the person I’ve been. I had issues, but we all do. I was a kid, and we all have to start somewhere on the long journey to becoming the people we want to be. Learn to be proud of who you are without hating who you’ve been. You have value now, and you always have. 2009-2016 16-23 497 lbs – 220 lbs. #transformationtuesday #weightloss #beforeandafter #thenandnow
From there, Diaz lost 122 kilograms — or 270 pounds — over a six-year period through a combination of healthy eating and regular exercise.
While he was proud of what he’d achieved, and quickly gaining a following for sharing his story and messages of body positivity, there was one thing he was yet to reveal: the loose skin left behind, which no amount of exercise could reduce.
In a Tumblr video last year, Diaz removed his shirt to show his followers the hidden reality of his weight loss, admitting he was scared of how they would respond.
Matt Diaz in his video last year. (Image: Tumblr/Matt Diaz)
"I wanted to share with you guys because I think it's important that I'm not ashamed about who I am because I worked really hard to get here, and I still don't have the body that I want but I'm trying really hard to love myself," he explained tearfully.
"I'm scared people won't think I'm attractive any more. I feel this all the time. Whenever I sleep with someone new, whenever I'm at the beach and I'm supposed to take my shirt off, I can't."
Watch: Meghan Ramsay on the effects of negative body image. (Post continues after video.)
The video attracted millions of views, and a GoFundMe page was set up to help the then-22-year-old raise the money required for skin removal surgeries. Now, a year on, Diaz has undergone two procedures on his stomach, sides and chest — donating the unused funds to others in his position.
As you might imagine, he's thrilled with the results. "When I see myself without the skin hanging from my body, I see the person I've felt like for a long time," he wrote on Instagram recently.
"I like who I am now. Not because of the surgeries, but because I realised my weight and my skin don't define my worth."
All marked up. A photo posted by Matt Joseph Diaz (@mattjosephdiaz) on May 17, 2016 at 9:30am PDT
In his typical open and honest fashion, Diaz has kept his fans updated every step of the process. There have been pre-surgery selfies and video blogs in describing the often painful reality of his recovery. Some observations have been humorous — "I look like the human version of a T-Rex" he admits in one video — while others have been more serious.
"The procedure was over three months ago, and I still find myself struggling to adjust. My body is still getting used to the change, and I'm still getting used to my body," he posted after his first surgery.
Diaz also allowed Buzzfeed US to live-stream his second procedure on Facebook.
Throughout his weight loss and surgeries, Diaz has maintained one philosophy: that his weight and appearance do not determine his worth. And that's an important one for all of us to remember.(Post continues after gallery.)
"Losing weight didn't fix my self confidence. It helped, but it didn't fix it. Losing weight taught me that I have to take care of my body, it taught me how to prioritize and how to work hard, but it didn't fix my self confidence. I felt thinner and more attractive, but I still felt insecure," he wrote on Facebook last year.
"What fixed my self confidence was realizing that my weight and my worth were not the same thing. I had value at 497 pounds and I have value now. Being healthier is wonderful, but your size does not determine who you are. Your character does."
Featured image: Matt Diaz/Facebook.