Legendary Australia cricket captain Meg Lanning struggled with "an unhealthy relationship" with exercise and food leading up to her shock retirement.

A self-described private person, Lanning has finally decided to share why she ended her international career last November at the age of 31.

The Victorian took an extended break from cricket in 2022, returned to lead Australia to a Twenty20 World Cup title in February 2023, but suddenly pulled out of last year's Ashes for undisclosed medical reasons.

Lanning has revealed she was grappling with an identity crisis outside of cricket that not even her teammates and closest friends knew about.

She was often only eating two "not significant" meals a day despite running up to 90 kilometres a week.

Lanning did not label her relatively insignificant food intake as an eating disorder — but admitted she was in denial about needing help.

"It sort of just spiralled," Lanning told The Howie Games podcast.

"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, mentally and physically.

"I got down to about 57kgs from 64kgs. The ratios were out of whack a lot.

"It was just all out of whack and I kept sliding. At some point, it's got to stop.

"I felt very out of control in terms of what my future looked like: 'If it's not cricket, what does life look like if I am not playing?'"

At her lowest, Lanning only slept for a "couple of hours" every night.