Rats will gladfully take most things you give them...especially the sweet or not-so-healthy kind. Below is a listing of what you do not want to give your rats for the sake of their health. Rats have a flap in their stomach that covers the esophagus and prevents both vomiting and burping. Since rats lack this ability to remove foods/fluids back out through the mouth everything must go completely through the entire digestive system before it can leave the body. There are some things that are complete NO-NOs and there are some things that you can feed in moderation.
Things to Feed in Moderation
plain popped popcorn
Vitakraft yogurt drops
avocado
chocolate
chicken or beef bones (cooked or boiled)
Kaytee chew biscuits
fruit Nutra*Puffs
vegetable Nutra*Puffs
dried corn
Nylabones for chewing
Foods high in nitrates: beets, celery, eggplant, lettuce, cucumber,
radishes, spinach, collards and turnip greens
coffee
Things To Never Feed
carbonated/fizzy drinks
foods (in excess) that cause gas
Orange Peels/Orange Juice (for males) - Pieces of the orange "fruit" are okay after washing
raw dry beans/Peanuts (contain anti-nutrients that destroy Vit. A
& digestion enzymes, causes red blood cell clumping)
raw sweet potato
green bananas (inhibits digestion of starch)
green potato skin and eyes (contains a toxin)
wild insects
raw bulk tofu
mouldy Cheese
liquorice (suspicions of neurological poisoning)
raw red cabbage (contains anti-nutrients that destroys thiamin)
raw artichokes (inhibits digestion of protein)
raw olysters/clams