Thanks to Therese O’Sullivan for sharing some Perth restaurant recommendations you might wish to explore whilst in Perth!
High cost options
Cant go past the Burswood Crown casino for a range of quality dining outlets, but they are pricey.
Rockpool is run by chef Neil Perry and is known for its steak. Silks is Chinese and they do dim sum as well as a la carte meals. Nobu probably has the best reputation, I havent been, but apparently the Nobu chain are some of the worlds best Japanese restaurants (part owned by Robert De Niro). It has a sake bar and tables where diners can view the chefs preparing sushi. I hear its good. Details for all of the Crown restaurants are here:
In the city one of the most popular ones is Balthazar, I’ve only eaten their once but it was excellent. Cosy, trendy little set up, food is locally sourced and the combinations they use work well together.
For a great view and ambiance, Frasers at Kings Park is a good pick. I havent been there for a long time but they used to do a lovely Kangaroo dish!  There are lots of nice walks to do around Kings Park, the gardens are fabulous and there is also a café there which provides cheaper options (standard café fare).
Amuse is tauted as Perth’s best restaurant, I havent been there but it consistently gets good reviews and publicity.
Medium and low cost options
Beaufort St Merchant has interesting meals and a provedore section with a variety of products. Pretty trendy place. I went there for a DAA WA dinner and the dietitians were happy with the food, which says a lot!
Little Creatures Brewery is popular as a medium cost option, the atmosphere is usually great and they do a reasonable pizza but the food isn’t extraordinary… the pale ale is good though!  Its in Fremantle.They also have a kids area out the back.
For something a bit different, the Raw Kitchen is popular and I’m sure dietitians would find it interesting! Also in Fremantle.
Annalakshmi – this vegetarian Indian restaurant operates on a ‘pay what you feel’ basis where they have a buffet set up and you pay on the way out whatever amount you want (I think around 20 is generally fair given the food quality). Its got a lovely view right on the river, the food is reasonable and the set your own price thing is a bit of a novelty.
The suburb of Northbridge just north of the city (walking distance) provides a lot of good value Asian dining options. S&T Thai at 349 William St and New Moon for yum cha at 63 James St.
Sienna’s do good value Italian, big serve sizes. They also have a kids play area inside! And often do deals like two-for-one and $15 mains.