The healthiest rabbit diet should be made up of unlimited fresh hay, a small amount of good quality pelleted rabbit food, and fresh leafy green vegetables. Anything beyond this is a treat and should be given in very limited quantities.
Avoid rabbit foods that contain dried fruit, nuts, and colored bits, as these are unhealthy for your bunny.
Adults, teenagers and babies should have an unlimited amount of fresh hay daily -- timothy, oat, or orchard grass for adults. Alfalfa is for babies only. Hay is nutritious, as well as critical roughage for prevention of life threatening fur blockages. A cat litter box filled with hay works well. Stuff empty, unbleached toilet paper rolls with hay to give your rabbit a project!
Provide unlimited fresh water daily, either in a water bottle or a crock that can't be tipped over. Adult rabbits should also have an assortment of fresh greens daily. Make sure greens are washed and haven't been sprayed. No beans, potatoes, rhubarb or corn. The closer to nature the better. Avoid yogurt drops and other sugary treats, as well as human crackers and sweets. A small piece of banana, apple, raisin, or berry will send your rabbit into bunny heaven!
If your bunny hasn't been on a healthy diet, you will need to make the switch gradually. A rabbit's digestive system is very sensitive, so avoid drastic changes.
Select at least three kinds of vegetables daily. A variety is necessary in order to obtain the necessary nutrients, with one each day that contains Vitamin A, indicated by an *. Add one vegetable to the diet at a time. Eliminate if it causes soft stools or diarrhea.
Carrot tops* (Carrots themselves are a treat)
Dandelion greens and flowers (no pesticides)*
Pea pods (the flat edible kind)*
Raspberry & blackberry leaves
Romaine lettuce* (no iceberg/light greenleaf)
* = Contains Vitamin A, please give one each day.
Alfalfa, radish & clover sprouts
Beet greens (tops)*
Apple (remove stem and seeds)
Orange (including peel)
Sugary fruits such as bananas and grapes should be used only sparingly, as occasional treats. Bunnies have a sweet tooth and if left to their own devices will devour sugary foods to the exclusion of healthful ones. Don't let them guilt you into giving the a whole banana!