But yesterday, he launched a NSW government pilot program - Healthy Heathcote - to encourage residents in his northern Illawarra electorate to join him on a year-long fitness regimen.

"People who have seen me will know how big I am, and I decided it was time to turn that around," he said. "I'm sick of being sick and tired. It's really hard to lose weight but I'm going to give it my best shot."

Although he had long been told by his doctor to drop kilos or risk developing type 2 diabetes, the tipping point for Mr Evans came on his 52nd birthday, when his wife presented him with a set of scales.

"That was last October and since then, I've lost 10 kilos," he said.

"So being the health doyen that I am, I'm going to be on a health kick for 2014 and I wanted to bring as many people as I could along with me."

After cutting back on big breakfasts, long lunches and late-night social engagements that are so frequently part of an MP's schedule and growing his own vegie patch to inspire healthy meals, Mr Evans approached Minister for Healthy Lifestyles Kevin Humphries with a plan to shrink the size of his electorate.

By signing up to Healthy Heathcote, participants from Bulli to Port Hacking will be able to take part in walking, yoga, bowling and gym classes, as well as healthy cooking classes.

They will also log their weight, blood pressure and other statistics with NSW Health, allowing the government to monitor changes in the fitness levels of the electorate during the year.

Launching the program in Engadine yesterday, Mr Humphries said he hoped to see Heathcote become the state's healthiest seat.

"Australia is experiencing unprecedented overweight and obesity levels and NSW, as Australia's most populous state, is no exception," he said. "The most recent statistics show that around half the adult population in NSW are overweight or obese, while 22.8 per cent of children between five and 17 years of age are overweight or obese."

Participants can register for the challenge at leeevansheathcote.com.au.