When deciding what vegetables to include in expert-recommended five a day portions, how does one know the right distinction between a fruit and a vegetable?
At first glance, this seems an easy enough task. That is, until a proper identification is attempted.
Professor Pauline Ladiges of the University of Melbourne's school of Botany says that the categorisation is simple.
"The ovary is the female part of the flower and after pollination (or fertilisation) the seeds develop protected inside the ovary, which swells and ripens. Fruits are often fleshy, coloured and sweet when ripened to attract animals to disperse the seeds."
Other fruits are dry and sometimes woody as in the case of eucalyptus (which are called capsules instead of gum nuts). Banksia and macadamias, which fruits are termed as follicles, are the same.
Therefore, if fruits are simply produce with seeds, then tomatoes, olives, cucumbers and legumes are all also fruits.
The science behind five a day portions of vegetables versus two a day portions of fruits is explained by the lower energy-density contained in vegetables compared to the energy-density of fruits.
Professor Ladiges then explains that vegetables are, technically, the non-flower parts of the plant. These are the leaves, stems, roots and tubers. Examples of these are spinach and rockett leaves, stems as celery and leeks, roots as carrots and turnips and tubers as potatoes and yams.
The confusion rose from the notion that fruits are sweet while vegetables are not. However tomato, peas and pumpkins disprove this conclusion since while they are fruits they are mostly used as ingredients for full-flavoured savoury cooking.
On the matter of the healthy practice of consuming five a day portions of vegetables and two a day portions of fruits, Professor Amanda Lee from the School of Exercise and Nutrition Science at Queensland University of Technology explains why we can still consider produce that we learned to use as vegetables rather than consume as fruits.
"Most relevant health studies, but not all, tend to use 'functional' categories rather than botanical categories of fruit and vegetables, because that's how those taking part in studies use these foods."