A DIET of fresh fruit and vegetables is better than once thought, new research finds.

It puts to rest the long-held belief a vegetarian diet was likely to lack protein and iron.

The review published in today's Medical Journal of Australia, shows a well-planned, plant-based diet can meet the nutritional needs of adults and children.

Scientists found fruit and vegetable-based diets reduced the risk of health problems such as cardiovascular disease, type 2 diabetes, hypertension and obesity.

Nutritionist Dr Rosemary Stanton said there were no significant health differences in babies born to vegetarian mothers.

The study, Is a vegetarian diet adequate?, showed there was no noticeable difference in the growth of vegetarian children compared to children who consumed meat as part of their diet.

"The average Aussie eats significantly more protein than is required by the body," Dr Stanton said.

"Not everyone needs or wants to become vegetarian, but eating more plant-based meals is a good recipe for our own health and that of the planet."

Vegan Shane Ward, 38, has lived on a vegetable-heavy diet for almost a decade.

"I'm fitter, healthier and stronger because I'm not using my energy to break down meat," he said. "I haven't been sick for years."