Australians are being urged to double the amount of exercise they do as part of revised dietary guidelines that also call for men to eat less red meat.
The National Health and Medical Research Council's guidelines - updated from the 2003 version - also urges new mums to breastfeed exclusively for six months to minimise the risk of their babies becoming obese or getting allergies.
The guidelines say Australians are still not eating enough healthy foods and have to curb their appetite for foods high in saturated fats and added sugar and salt.
In a grim warning, 83 per cent of men and 75 per cent of women will be overweight or obese by 2025 if current trends continue.
Two-thirds of men and 53 per cent of women are now carrying too much weight.
"The evidence has just got stronger and stronger over the last decade about what is healthy and what is not," council chief Professor Warwick Anderson said.
"Too many of us are eating too much, especially of those foods which we know we shouldn't eat."
One big change in the guidelines is exercise, with people told to aim for between 45 and 60 minutes a day of moderate exercise to maintain their weight. Formerly obese people should do up to 90 minutes to keep the kilos off.
Nutritionist Rosemary Stanton, who was on the panel that revised the guidelines, said the long-established recommendation to exercise for 30 minutes daily had been aimed at cardiovascular health but when it came to fighting fat, people needed to do more.
"For obesity, it's a greater amount but spread throughout the day seems to be even better than doing it all in one go," she said.
The guidelines state Australians need to eat more fruit and vegetables, poultry and seafood, eggs, wholegrain foods and low-fat milk, yoghurt and cheese.
Men should cut their intake of red meat by 20 per cent but young women should eat more of it.
Alcohol should be limited and pregnant and breastfeeding women should not drink alcohol at all.
The guidelines around sugar have been toughened, with stronger evidence emerging that sugar-sweetened beverages such as soft drinks cause weight gain.
Ruby Osman-Mulraney said she and her partner, WA cricketer Nathan Coulter-Nile, were already aware of many healthy diet principles because of his athletic career and they were trying to pass that on to their daughter Amelie, 2½.
She said she sometimes found it difficult to know what to feed her child because of conflicting dietary advice. She tried to get her daughter interested in food and takes her to a farmer's market every weekend, allowing her to put her choice of fresh food in her own basket.
"I think food should be enjoyed. Obviously it's a fuel and you have to make sure it's good for your body," she said.
Ms Osman-Mulraney, 24, said she understood it was hard for busy parents to have healthy, fresh food always on hand for their children instead of grabbing convenient, but less healthy, snacks on the run.
"With kids it's really hard being prepared in advance and that's something I'm still learning, to prepare in advance," she said. Ms Osman-Mulraney said when it came to her own diet, she ate the same as her cricketer partner and her child and avoided unhealthy, processed food as much as possible.
"A lot of people know what they should and should not eat, but they are in denial," she said. "They think I can eat this burger and chips and my body will be OK with it, even when they get spotty skin and dry hair afterwards."