Could you keep up with this 38 stone man?
When Derek Mitchell hit over 600 pounds (43 stone), he decided to make a change.
He vowed to run at least one 5K a month and now has exceeded those expectations and is an inspiration to all.
See also: Shocking celebrity weight changes
Derek was diagnosed with a benign tumour on his pituitary gland, causing him to gain weight.
He found inspiration and a way to change his life by running.
He said: "The running community is kind of a hidden gem. So incredibly supportive and encouraging.
"That moment when you're running to the finish line, and everyone is cheering and everyone is clapping, it's absolutely amazing.
See also: The air you're breathing could be making you fat
So far Derek has done twenty 5ks, two 10s, and half an obstacle course, totalling more than 155 kilometres in 2015.
Derek's lost over four stone and, for 2016, he aims to run even further and faster.