Born in Nigeria, Chiadika Uzor was about 11 when her family moved to Ireland in 2006, settling in Dublin.
Now a 19-year-old medical student at Trinity College, Chiadika recalls how her weight crept up in the years that followed: "I'd always struggled with my weight but it started to get worse as I reached adolescence."
"I was too comfortable! I was eating everything and picking at things even when I wasn't hungry.
"I was no good at sitting down and just having my regular meals – I had no control.
"Being big is in the family and my mum was always conscious of this and tried to help me to control my eating.
"I'd have my dinner – and it would be a reasonable portion – but after dinner I'd want a snack.
"I always had to pick on something, usually when there was nobody around."
She wasn't much into sweets or crisps – but, she recalls, she ate quite a lot of bread and "really starchy carbohydrate food like rice."
"Bread was a big one for me. I like white bread and I ate a lot of it."
By the time she was about 13, her mum was getting very anxious.
"Mum started to notice things – I was having trouble putting on my shoes and socks. I was breathing heavily and had very poor balance."
At 13, she recalls, although she was only about 5ft 4ins in height, she weighed over 250 pounds (over 113 kilos or around 17-and-a-half stone.)
"Mum was very worried. The first time I realised there was a problem was one day when I was walking to school and I suddenly started breathing very heavily. My sister asked if I was okay, she said I seemed as if I was going to pass out."
Then came the game-changer: "One day my mum got me a pair of trousers. They were size 20 and they didn't fit.
"I was 14 at the time, and I was very upset about this. That was the start. I kept those trousers as a warning to myself and started exercising.
"I'd get up in the morning and walk before school or do a slow job when it was still dark – then I'd go to school.