Dogs who are working hard need more energy. The carbohydrate sources he recommends are rice, potatoes, tapioca and macaroni. Most of the diets include a little vegetable oil, maybe some salt, some bone meal for calcium and phosphorous, and a multiple vitamin-mineral tablet. The correct balance of vitamins and minerals is critical. Some are toxic if too much is consumed.
Deficiencies can, with time, cause serious disease, especially in cats.
There is also a wide array of vegetables in many of the diets. The cooking is pretty simple. You don't have to make any fancy sauces or glazes. You don't have to use any exotic combinations of spices or herbs. In fact, I would advise taking care to avoid these things - they are probably a common reason for pets having diarrhea and upset stomachs from eating human food.