Australian comeback swimmer Geoff Huegill has confessed he used recreational drugs and abused alcohol and junk food while suffering from depression in the wake of his retirement after the 2004 Athens Olympics.

Huegill put on 45kg before returning to the sport in 2008 and winning two gold medals at the 2010 Commonwealth Games in Delhi.

He said the swimming world was intensely sheltered and he'd struggled to cope with reality when he retired, which caused him to turn to alcohol and drugs.

He thanked his wife Sarah, and coach, Keith Saggers, for helping him back on track and back to fitness.

Huegill is now an ambassador for the Black Dog Institute's Exercise Your Mood Campaign, which promotes exercise as a way to help beat depression.