There are plenty of rat food brands available at pet stores but it is important to know which ones are actually suitable for rats. Brands such as Tui and Topflite are not suitable for rats as they mainly consist of seeds which should be avoided as their nutritional value is low, meaning they are unhealthy foods for rats.
Brands such as Vetafarm Origins, Science Select, Burgess and the NZ Rat Rescue mix/lab blocks are all suitable foods for rats. Apart from the NZ Rat Rescue mix which can be purchased at their store, all the other recommended brands of food can be purchased at pet stores such as Animates.
Along with dry food you can feed your rats a variety of fresh vegetables and fruits. Leftovers from dinner will always go down well but make sure that they are safe for rats to eat.
For some information on diet and foods to avoid check out the Rat Club page.
TOXIC FOODS
Blue Cheese - the mold in it is toxic to rats.
Green Bananas - inhibits starch-digesting enzymes.
Green Potato Skin and Eyes - contain solanine, a toxin.
Licorice - suspected to cause neurological poisoning in a rat.
Orange Juice - forbidden for male rats only, the d-limonene in the skin oil can cause cancer.
Mango - also forbiddon for male rats only, due to the d-limonene in the flesh.
Raw Artichokes - inhibits protein digestion.
Raw Bulk Tofu or Meat- can contain bacteria, packaged raw tofu is safe.
Raw Dry Beans or Peanuts - contains antinutrients that destroy vitamin A and enzymes needed to digest protein and starches and causes red blood cells to clump.
Raw Red Cabbage and Brussel Sprouts - contains antinutrient that destroys thiamin (cooked is fine).
Raw Sweet Potato - contains compounds that form cyanide in the stomach (cooked is fine and a hit with most rats).
Avocado skin and pitt - toxic to rats. The flesh is fine.
Rhubarb - contains high levels of oxalates.
Sticky foods such as Peanut Butter, some Candy, and Dried Fruits - poses a choking hazard. Peanut butter can be "cut" with jam or honey to make it more liquid, and reduce the possibility of choking.
Seaweed - the seaweed the comes on sushi or in soup poses a choking hazard.
Wild Insects - can carry internal parasites and diseases.
UNSAFE FOODS
Carbonated beverages. Rats can't burp, so drinking them can cause discomfort.
Dried corn. Contains fungus known to cause cancer in rats, so limit the amount you give them. Some fresh corn is ok in moderation.