Age

• A general rule of thumb in the pet food industry is small breed dogs should transition from puppy to adult food at 1 year of age, medium breeds at 1 1/2 years old, and large breeds should wait until they are close to 2 years old.
  
  

Time Frame

• When making the transition from puppy to adult dog food, do it gradually. An abrupt change in diet can cause stomach upset and diarrhea.
  
  

Method

• Take 2 weeks to transition to the new food. For the first few days, offer meals with 75 percent puppy food and 25 percent adult food. Then gradually increase the percentage of adult food until the dog is eating 100 percent adult food.
  
  

Effects

• Puppy food is very rich. When fed to adult dogs that don't need the extra proteins, they may get overweight, causing further health concerns.
  
  

Types

• There are many types of adult dog food, from breed-specific formulas to ones that address adult issues such as sensitive skin, sensitive stomach, allergies and digestion concerns.