Swimming champion Michael Phelps struggled with a weight problem after giving up sport following his eight-medal win at the 2008 Beijing Olympics.
The sportsman put on a massive 25 pounds (11 kilograms) when he stopped swimming in the wake of his big victory and didn't realise he needed help until one of his friends pointed out his weight gain.
He tells Details magazine, "It was weird going from the highest of the high, the biggest point of your life - winning eight gold medals - and then saying, 'All right, where do I go from here?' I wasn't motivated. I did nothing, literally nothing, for a long time. I gained 25 pounds... A friend of mine and I were playing football on the beach in Miami and somebody got a picture of us... (My friend said) 'Bro, you gotta start working out, man. You are fat.'"
Phelps, 27, started exercising again and is now preparing to represent the U.S. at the upcoming 2012 London Olympics.
He adds, "I realised that I probably hadn't reached my full potential. There was still more in the tank... At this point in my career, everybody has caught up. I'm fine-tuning the little things that add up to make a huge difference."