I am guessing but I think you will probably find more things you can eat ordering the gluten free meal. Go to the airlines website and see if they have sample menus or call the airline. I know American Airlines has sample menus.
You will need to also bring your own food on the airplane. I always make sure that I have 50% more food than I think I need in case of delays or my gluten free meal does not make it onto the plane (yes, this has happened to me

)
Liquids are not all allowed through security, including such things as yogurt and pudding type food. You should be able to bring solid food thru security.
I have brought the following:
Vegetables that can be eaten - raw carrots, cauliflower, broccoli, slice tomatoes, etc…..
Fresh Whole Fruit - apple, orange, banana, berries etc…..
Gluten Free Chips - potato, corn or tortilla
Gluten Free Bars - Glutino, Enjoy Life, Lara
Hard Cheese
Sensible Foods – Crunch Dried Fruit (www.sensiblefoods.com)
Nuts
A few slices of Gluten Free Bread
Pre-made Peanut Butter and Jelly Sandwich on Gluten Free Bread
I have seen in other posts that Bananas and Cheese have been taken away. I have not had this happen to me.
I have a doctor’s note requesting that I be allowed to bring Blue Ice through security to keep my food cold because I am on a medically restricted diet. That said, I have not had to use the note.
I cut off a small piece of a Blue Ice Mat and put it into my soft sided lunch box. I put the lunch box into my carry on luggage. This has gone through security without any problems so far, but be prepared to have the blue ice taken away.
An alternative that I used on a trip was to bring along a Ziploc bag. I was able to have it filled with ice where I bought my water and juice for the trip.
To be sure of the current carry on restrictions you can go to the TSA website below for your outgoing flight.
http://www.tsa.gov/travelers/index.shtm.
I would suggest you investigate the any restrictions on food entering Australia. On returning to the US fruit, vegetables and meat are not allowed in (double check the rules). If I have any of these I give it to the flight attendent as trash before the plane lands.
Also, you may want to do some research about Australian airport security for your return trip.
Have a supper trip