Women are likely to be warned that they could be eating poorly during pregnancy and harming the future health of their child, as part of a plan to reduce New Zealand's childhood obesity rates.
Health Minister Jonathan Coleman, who will launch the plan today, said most Kiwi women gain too much weight in pregnancy.
"Around 60 per cent of New Zealand mums gain more weight than recommended during pregnancy.
"We need to start early in life, very early. There is growing evidence of the importance of prenatal habits and its relationship with the hardwiring of a child's eating habits going forward," he said.
Overseas, recent advertisements have warned mothers, "Your child is what you eat", with one viral campaign by Brazil's Pediatric Society of Rio Grande featuring a picture of a mother breastfeeding, with a burger painted on her breast.
Despite New Zealand's very high adult obesity rates - the third highest among OECD countries, with more than one million adults obese - the decision has been made to focus on childhood obesity.
"We are taking a life course approach, which is evidence-based," Dr Coleman said. "By focusing on children we expect to also influence the whole family."
Being overweight or obese is expected to overtake smoking next year as the leading preventable risk to health in New Zealand.
However, unlike tobacco, the Government will not try to change behaviour through new taxes, despite calls from health professionals to do so.
Dr Coleman said a sugar tax was "not workable".
"The jury is still out on whether a tax on sugar sweetened beverages actually reduces rates of obesity. We continue to follow the evidence as it evolves."
Labour Party health spokeswoman Annette King has said the party would not tax soft drinks as that would not address the problem of sugar levels in processed foods.
Instead, Labour would give manufacturers a chance to significantly lower sugar content, making clear that regulation would be used if that did not happen in stated timeframes.
Green Party health spokesman Kevin Hague said last week that the obesity plan needed to show the Government was not "beholden to the junk food industry".
"The first step should be bringing back the food in schools guidelines that National discarded when they came into office," he said.
"At a very minimum, we should not be allowing junk food peddlers to sell sugary food and drink to our kids in schools. There should also be a tax on sugar-laden drinks."
In 2005, Dr Coleman told the Herald while campaigning for the seat of Northcote that it was important to get junk food out of schools.
"I can show you primary schools in South Auckland where kids have a $1 pie for breakfast from the school tuck shop, then follow up with more of the same for lunch. That's what has to stop," he said.
It is not clear if there will be junk food bans in today's plan, which was developed with the Prime Minister's chief science adviser Sir Peter Gluckman.
School anti-obesity projects are likely to feature, and the way physical education is run could change.
•The Government will today launch a major plan to reduce New Zealand's childhood obesity rates.
•About 10 per cent of all New Zealand children aged 2-14 years are obese - around 79,000 youngsters. Fifteen per cent of Maori and 25 per cent of Pasifika children are obese.
•A third of New Zealand adults are obese, and a third are overweight.