There are a few different schools of thought on whether or not you should slip your dog the occasional bit of your dinner, but I liked this answer from Drs. Foster & Smith, a leading pet supply company.
Is it ok to give dogs healthy table scraps?
You can give your dog table scraps, provided that they are low in fat and sugar, but treats developed for dogs are a much better choice. Just make sure that treats or table scraps do not comprise more than 10% of your dog’s total diet. If you do give your dog table scraps, give samples of foods such as rice, green beans, or a scrap of lean meat. Avoid fatty foods like chicken skin, or the scraps of fat you’ve trimmed off your dinner steak, as well as high-sugar foods like candy and baked goods.
Be aware, however, that by feeding table scraps, you’ll typically have a lifelong “beggar” at your table whenever you eat. Further, feeding table scraps may encourage your dog to steal food left on the table unattended - some of which could be hazardous to your dog’s health.