Former Australia cricket captain Meg Lanning said Thursday that an unhealthy "obsession" with food and exercise led to her sudden international retirement last year aged just 31.

Lanning skippered Australia's all-conquering women's team for almost a decade, winning four Twenty20 World Cups, a 50-over World Cup and Commonwealth Games gold.

But behind the star batter's cool exterior she says that she was struggling.

A private person, Lanning told an Australian cricket podcast that to escape the pressures she began running up to 90 kilometres (56 miles) a week, but did not eat enough to fuel her "obsession".

She said she lost significant weight, struggled to sleep, became moody and withdrew from people close to her.

"I was over-exercising and under-fuelling," said Lanning, who earned the nickname "Megastar" for her run-scoring exploits.

"It sort of just spiralled and I was in denial, even though everyone kept telling me something wasn't quite right.

"I was not in a place to be able to go on tour and play cricket and give the commitment levels required for that Ashes series (in 2023) mentally and physically."

Lanning, who has continued playing in the Women's Big Bash League and the WPL in India, declined to label the problem an eating disorder.

But she eventually sought help after it began affecting her life.

"I am naturally fine spending time with myself but there were very few people who I would want to engage with. I would get really snappy, real moody, if anyone asked anything," she said.

"I disengaged a lot from friends and family. I didn't realise that I was doing this. It sort of became a new normal."

With the demands of being captain and touring the world a thing of the past, Lanning said she was now "in a good spot".

"I've really started to understand how actually talking to people and letting people know can actually help," she said.