Aaron Harlow-Stephenson, 21, from Aykley Heads, Co Durham lost 10 stone and turned his life around after being bullied in school about his weight.
He spent his teenage years, hoarding and devouring crisps, ready meals and chocolate before starting a fitness regime.
By the time he was 16, he weighed 147 kilos - more than 23 stone.
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The former fireman now competes in body building competitions and creates personalised diet and fitness plans via his Facebook page completely free of charge because he “wants to help people.”
He said: “The turning point was in college when somebody walked past and said ‘who ate all the cakes’ and that just sparked something and made me want to change my lifestyle.
“I took up rugby and kept to a strict diet – I lost 10 stone and kept fit through my work as a fireman and trained as a bodybuilder.”
The 21-year-old now trains in the gym for roughly three hours and runs up to 5K each day while sticking to a 2,100 calorie diet consisting of chicken or turkey and celery.
He added: "People seem surprised that I’m giving fitness advice for free, but with so many people at home and comfort eating, I wanted to find ways to help them with them physical and their mental health.”
Aaron who is now an ambulance clinical care assistant, helps create plans for a wide range of people from a pensioner with arthritis to a 14-year-old boy who wanted to build his strength and his confidence.
He said: “I just wanted to help people and without charging a fee you really connect with people a lot more, people tell you exactly what they’re struggling with.
"Sometimes it’s not just fitness related advice, I help with mental health too.”
So far, the fitness guru has gained more than 83,000 Instagram followers and created upwards of 300 plans.
He added: “It’s more than being just about fitness, I help anybody that contacts me, sometimes people just want to chat and I’m more than happy to help anybody in anyway I can.”
You can find more information about Aaron’s fitness page here.