Obesity is a disease outside a person's control, says support group 

Susie Birney: 'I was always very active, so this "eat less, move more" didn’t make sense in my life.' Photograph: Abbie Trayler-Smith.

When Susie Birney started gaining weight as she hit puberty, she was convinced she had a food disorder. 

Over the years, as she gained more weight, she listened to her peers and tried eating less and exercising more.