As mentioned, adult dogs usually only need to eat once daily. Some smaller breeds may do better if fed twice daily. What to feed The choice of what to feed is obviously up to the individual owner. The choices available are canned food, semi-moist foods and dry foods. All three types are nutritionally the same and are complete rations by themselves.
Canned foods are three-fourths water and thus cost more for the same amount of nutrients.
Likewise, semi-moist foods require special processing and packaging, which add to the cost. Dry foods are the most cost-effective and require the least amount of storage space. Dogs do perfectly well eating only dry dog foods. Once the type of food has been decided, you should not change back and forth. Changing from different types or brands of dog food can upset the dog's system and lead to vomiting or diarrhea.