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Anna Boniface seemed to have the world at her feet when finishing as the 2017 London Marathon's fastest amateur female runner.
Her performance earned her an England team place in that autumn's Toronto Marathon. The then 25-year-old finished the London race in two hours, 37 minutes and travelled to Canada six months later.
But 10 miles into her international debut, Anna's ankle fractured.
"It was the breakthrough that broke me," she tells BBC 5 live Investigates.
"It was horrible, I'd never not finished a race in my life. I thought I could just struggle to the end somehow, but I realised I would not be able to go on, I just had to sit on the kerb and wait."
But worse was to come for the Reading runner. In addition to the stress fracture of her ankle, tests found poor bone density, including osteoporosis in her spine, which made fractures a real risk.
These symptoms were all hallmarks of a condition called Relative Energy Deficiency in Sport (Red-S).
This occurs when sports people restrict their diet in the belief that constant weight loss will keep improving performance, to such an extent that some of the body's functions begin to shut down