My dogs eat fruits and vegetables. They especially love carrots but don't mind eating leafy greens, mangoes or even apples. I don't feed them grapes but I do spoil them with carrots sometimes.
Although dogs are able to survive eating fruits and vegetables alone, it's not highly advisable because their digestive system was meant to consume meat. Even though dogs can derive protein from plants, their genetic traits and digestive system is biased for meat consumption. In short, their bodies are optimized to eat meat.
If you want to learn more about the dog's diet, here's an article that would shed some light on this matter. Are Dogs Carnivores — or Omnivores?
