He was overweight, ate too much and wanted to do something about it.

When he heard about a University of Newcastle study on addictive overeating, he jumped at the chance to be involved.

"It's been really useful for me," Mr Mayo said.

"Basically, I have this food addiction. I don't know why I have it, but I have it. For me, following a diet isn't so much the answer," he said.

The university researchers helped him understand "why I have this relationship with food and how to cope with that".

Mr Mayo, of Newcastle in NSW's Hunter region, urged others to get involved in the study, which is now seeking more volunteers.

"They don't put you on a diet. They look at your eating habits," he said.

"They don't tell you what to do, it's much more about behavioural change associated with understanding the addiction to food and how to manage what you eat and the amount you eat. I suspect there are a lot of people like me, which is why I'm comfortable sharing my story."

Professor Tracy Burrows, who leads the study, said addictive overeating that affects people's day-to-day lives afflicts about 15 to 20 per cent of the population.

The free program is called TRACE [Targeted Research on Addictive and Compulsive Eating].

"We are over halfway through our study and looking for more adult males and females who experience addictive eating behaviours to trial the online program," Professor Burrows said.

The nutrition and dietetics researcher said people who had been through the program were pleased it was "not weight-loss focused and more about improving their relationship with food for lifelong changes to their eating habits".

Participants say the program increases their self-awareness about eating, which the researchers consider an important step towards change.

The program teaches coping strategies to help people create better habits.

Mr Mayo said the strategy that worked best for him was called "surf the urge".

"The researchers taught me to pause, think about it and move on," he said.

"My wife is very health conscious and I get good food at home, but it's what I do outside of home. I'm talking about walking into a service station and seeing a chocolate bar or doughnut.

"Because I'm much more aware of it, I just think 'come on, surf the urge, you don't need that'."

The researchers also taught him to savour food rather than eat fast, so he doesn't feel he has to eat so much. "When I taste the food, it satisfies me a lot more," he said.

Mr Mayo said he was "a fairly active sort of bloke".

"I'm not sedentary. I don't sit around watching TV. I ride a bike, walk and I'm in the surf club."

He said the program had helped him look within.

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"You've got to confront yourself," he said.

"They talk to you about how to adapt your thought processes to eating. It's more about what's between your ears."

He enjoys a beer, but realises there are "times I don't need those two or three extra schooners".

"I can do without them."

Mr Mayo said he tended to eat when bored.

"I eat because I can. I eat because it's there," he said.

He would often eat something in a minute, but not feel any better for eating it.

Then he'd think "I probably shouldn't have eaten it".

One of his coping strategies was to think "it's OK to be bored". And there is no shame in setbacks.

"If you fall off the wagon, it's not the end of the world. Within 12 hours, it's all behind you and you just keep going," he said.

Mr Mayo weighed about 115 to 120 kilograms before starting the program.

"I'll never be skinny, but I've lost 14 kilograms. My aim is to get down to 100 kilo and see where we go from there," he said.

Since doing the program, he thinks about "what I'm going to eat each time I have a meal". "After my recent blood tests, my GP said 'whatever that TRACE program is doing with you Mayo, just keep doing it'."

To be in the trial, email traceresearch@newcastle.edu.au or visit the website redcap.link/trace_study.