Young puppies, especially toy breed puppies, need to eat every few hours to avoid dangerously low blood-sugar levels. As your puppy grows, you can decrease the frequency of the meals based on your veterinarian’s recommendation.
Adult dogs, on the other hand, do not need as many meals as puppies and can go for longer between meals. Veterinary nutritionist Dr. Amy Farcas says that most healthy adult dogs are perfectly fine eating two meals a day. Your dog does not need a lunch, despite what he may tell you, and most dogs adjust very well to this twice-a-day schedule.
There are exceptions to this. Dogs on a weight-loss diet might do better with several small meals over the course of the day to help them feel less hungry, and dogs with health conditions like diabetes or cancer might require a specialized meal plan. Feeding one meal a day is not typically advised by veterinarians, especially for large dog breeds. All of that food, and the speed with which it is consumed, could lead to bloat.