Yes you can use canned fruits and veggies. However, canned veggies have been heated during the canning process so some nutrients may have been lost. If using canned, be sure to choose ones that do not have added sodium or oil. Try to get frozen if you're having trouble finding fresh. The same goes for canned fruit, fresh or frozen would be better options if available, but If you're using canned, then choose ones without added sugar and are not packed in a syrup. Ones packed in water would be the best choice.