1. Leafy Greens: Inside cats normally don't have access to greens (like cat grass - unless you grew it for them) so giving them some tender leafy greens to nibble on is a great treat. Will your cat eat it? If they crave it enough, they will. Many cats love leafy greens! Cats normally eat grass to help with digestion and for some extra hydration, so providing your cat with leafy greens will help them achieve just that.
2. Green Beans: Slightly steamed green beans are great for cats! Studies in humans, cats and dogs have all substantiated positive weight loss results when adding green beans to their diet (mainly due to the high fiber and nutrients in the beans). Green beans will reduce the amount of times your cat begs for treats in between meals, as it will keep them fuller longer. If your cat is over weight, consider using green beans as a between-meal treat!
3. Carrots: Carrots are a great food to feed to your cat, especially when slightly steamed and mixed into their food. They are high in beta-carotene, which isn't as readily converted in the feline species to vitamin A, however the other nutrients and fiber in carrots will certainly not hurt your cat! Carrots contain vitamin B, C, D, E, K, calcium, postassium, riboflavin, sodium and iron, all of which will keep your cat in tip top shape!
4. Asparagus: Asparagus, just like other green vegetables, are great for your cat (especially if they are in-door cats and don't have access to grass outside). The fiber will help regulate their bowels, and they are a great way to get in some hydration in your cat (since cats are not too fond of drinking water). Asparagus benefits the liver, and is very high in vitamin C, selenium and low in sodium.
5. Broccoli: Sometimes cats actually crave vegetables! One of my cats went nuts over broccoli, and loved chewing on some raw broccoli from time to time. If you notice your cats eating your house plants (which they shouldn't be doing - some house plants are toxic to cats!), feed them some raw or lightly steamed broccoli. This could satisfy their desire for greens and can help clear up digestive issues
6. Winter Squash: Will need slight cooking to soften the rind. Pumpkin and other winter squashes are great for felines suffering from constipation or diarrhea. Use small amounts (1/2 tsp) mixed into several of the daily meals. The beta carotene in squash is excellent for the health of your feline as well.