Advanced accredited practising dietitian Dr Kate Marsh tells us that apart from vitamin B12 it's certainly possible to meet all your nutritional needs on a vegan diet if you eat a wide variety of whole plant foods.

"The main thing is thinking about what you're cutting out (animal protein) and making sure the replacements are providing important nutrients such as iron, zinc, calcium and omega-3 fats," says Marsh. "This means regularly including foods like legumes, tofu or tempeh and nuts and ensuring you're eating enough of them."

While many people worry about getting enough iron without red meat, there are plenty of iron-rich plant foods including legumes, wholegrains, nuts, dried fruits and dark green leafy vegetables. 

But Marsh does sometimes see iron deficiency, mainly in teenage girls.

"Usually the issue is that they've gone vegan and cut out meat, but haven't replaced it with iron-rich plant foods. Often it's because they're not familiar with these foods, so need ideas of how to incorporate them into meals, particularly when the rest of the family are still meat eaters."

It's the one nutrient you can't get from a plant-based diet, and while some vegan products are fortified with B12 – nutritional yeast and certain soy milks and mock meats, for example – you'd need to eat them regularly and in reasonably large quantities to get enough.

Much like 'gluten free', 'organic' and 'natural', there's a health halo associated with the word 'vegan'. People may think the vegan donuts and ice creams appearing on menus, in the supermarket and being spruiked at vegan markets are healthier than the non-vegan versions, but usually they're not.

Like any processed foods, processed vegan food products can be high in less desirable nutrients such as added sugar, saturated fat and sodium (see vegan cheese). Hubba Bubba Bubblegum, Arnott's Choc Ripple Biscuits and BBQ Pringles – all of which are vegan – are cases in point.

"All the research we have showing the health benefits of veganism is specific to whole food plant based diets," says Marsh. "So while it's possible to follow a vegan diet predominantly eating processed vegan foods, you're not going to get the same benefits as a diet based around whole foods such as vegetables, fruits, legumes, minimally processed wholegrains, nuts and seeds."

Consider contacting Vegan Australia to find out more about how to go vegan, and consulting an accredited practising dietitian with a special interest in this area to make sure your diet will meet all your nutritional requirements.