Weight debate a stress for mums

Aja Rock's post-baby selfie.

Focus on eating well for baby, not on 'Hollywood' figure.

A leading nutritionist has responded to a boasting post-baby Aja Rock with a warning - women should ignore unrealistic "Hollywood" pressure to look trim after giving birth.

The 32-year-old Auckland socialite has this month re-ignited debate about the pressure on women to lose their "baby weight", posting an intimate "selfie" one week after giving birth to her third child, daughter Lilly Vonn. The Twitter photo shows her flat stomach and is tagged: "Time to claim my tummy back. #oneweekpostbaby".

She also raised eyebrows at last week's E! Channel party in Auckland, proudly showing fellow guests her flat stomach.

But Healthy Food Guide nutritionist Claire Turnbull said weight gain during pregnancy was normal, and it was time women ignored the unrealistic "Hollywood" pressure to look trim after giving birth.

Turnbull - expecting her first child in eight weeks - said the weeks after birth was no time to punish your body through restricted diet.

"The last thing you need to think about is getting back into your bikini," said Turnbull.

Instead, new mums should be focused on nurturing their newborn, getting sleep and eating a good diet to help breastfeeding and recovery from birth. Turnbull said a woman could expect to gain 11kg to 18kg during pregnancy. And if a mum breastfed, energy requirements would remain high which could mean eating more food.

It was unrealistic and unhealthy to expect the weight gained gradually over nine months to be lost overnight.

Said Turnbull: "It takes time to shrink back - more than a week."

A combination of healthy diet and active lifestyle would see the weight gradually drop off, she said.

Auckland clinical psychologist Dr Natalie Flynn, who has specialised in postnatal depression and eating disorders, said new mothers were vulnerable to postnatal depression if they had unrealistic expectations.

"When we do have these high expectations of ourselves."

Susanne Trim of the Nurses Organisation also condemned the expectation on women to shape up quickly.

"Certainly it's an unrealistic expectation to have a flat stomach a week after birth, and it does create a sort of societal pressure on women to conform to a so-called good body image."

Stress and anxiety about body image could drive women in an unhealthy direction, she said, possibly leading to unhealthy dieting.

New mothers needed to focus on their baby and getting comfortable with the changes in their life, Trim said.

"As well as having the physiological changes, they're trying to bond with the new baby and adjust to a completely different sort of lifestyle and dynamic and lack of sleep - so it's an unrealistic expectation and it creates poor messages, I think, for women."

Rock's daughter Lilly spent the first days of her life in Auckland City Hospital's newborn intensive care unit after being born prematurely, but is now home.

Rock did not respond to requests for comment.