I will feed my dogs sensibly and will not allow them to get fat. Your vet can advise you about your particular dogs' dietary needs. The dog food book by Liz Palika is excellent, and most dog journals periodically run features on nutrition. Just as important as providing wholesome food is preventing illness from toxic substances. I will take care to keep poisons away from my dogs.
Many common substances are harmful to dogs.
As to foods, the most important one to remember is chocolate . To a lesser degree, some ingredients in table foods may interfere with digestion even if not actually toxic. Among plants, the common houseplants diffenbachia and philodendron are poisonous, as are many popular landscape plants like oleander. My dogs deserve clean dishes and clean quarters. Also, their teeth will get cleaned before decay sets in.