Healthier meals are increasingly becoming priorities for many health conscious Melburnians. A gourmet salad with a beautiful assortment of greens and meat(optional) can be an excellent meal to satisfy anyone.
There is a place called Found off Chapel that serves some nice beef and prawn salad, although it seems they mainly deal with breakfast. Shakahari Too in South Melbourne is a really nice place for vegetarian, last I heard. If you are looking for somewhere closer to the CBD, then the restaurant on Lt Collins is a good one.