• 43 per cent of menus offered children's drinks, with most being mocktails, spiders, soft drinks and juices.
Heart Foundation food and nutrition manager Dave Monro said while most adult menus offered a variety of healthy options, children's menus lacked them.
"What we're seeing is a lot of fried foods, high-sugar beverages and very few vegetables being offered to children when they're dining out with their parents," he said.
The results were "highly concerning" because about one-third of Kiwi children were overweight or obese.
"Children who are overweight or obese face a greater risk of developing heart disease, diabetes and high blood pressure as they grow older."
Mr Monro said although parents and children often wanted a treat when eating out, unhealthy items shouldn't be dominating the menus.
The solution was to offer smaller portions of healthy adult dishes to children.
There should also be vegetables available in main meals for children, and salad or colourful vegetables on the side of others.
Improving children's menus would also help Kiwi kids develop a taste preference for healthy food, he said.
"By turning the traditional kids' menu on its head and offering more healthy choices and less of the deep fried options, chefs and restaurateurs will be investing in their future customers."
Auckland clinical nutritionist Shona Wilkinson, who specialises in children's nutrition, agreed with the solution to offer them smaller adult meals. "The challenge is that children can be difficult to please so dishes need to be simplified to suit their tastes."
She said the current meals offered to children were "so simplified that a lot of the nutrition has been removed".
"So mum and dad are eating a beautiful steak while the child is sitting there eating inexpensive battered fish."
Although children could be hard to please, the Heart Foundation's proposed solution was a chance to reinforce healthier choices. "Healthy food doesn't need to taste bland," Ms Wilkinson said.
The Restaurant Association could not be reached for comment last night.