Greg Osborn doesn’t beat around the bush.

“I’ve been pretty fat my whole life,” he says.

At his heaviest, he weighed 130 kilograms, and has spent most of his life between 120 and 130 kilograms.

He says his size restricted his lifestyle to such an extent he was unable to go for a swim or “do energetic things with the kids”.

It wasn’t until his 58th birthday that he decided enough was enough.

Both his father and brother had died at 60, and he was staring down the road of a similar fate.

“The thing that was going to kill me was all the extra weight,” he says.

So the Taylors Lakes resident cut out all processed and junk foods, until he got down to 110 kilograms.

Then he started running.

“Just short ones,” he says.

In 2008, his daughter entered charity event Run for the Kids.

He wanted to join in, but travel plans were in the way, so the following year he entered the half marathon event.

“I saw all the runners doing the marathon and I thought, there’s no way I could do that.

“Then I saw on The Biggest Loser – they made them do it – so I entered into the Melbourne marathon in 2010.”

The former police officer is now down to 90 kilograms and has run 12 marathons, including in Paris, London and New York.

He has also entered into this year’s Medibank Melbourne Marathon Festival for the fifth time, ensuring he’s on track to complete 10 Melbourne marathons by the time he is 71.

“A lot of people have said to me, ‘how do you get by without the good things in life’, and I say, the good things in life can’t be stuffed in your face.”