What happens if I switch to adult food too early?

For large and giant breed puppies specifically, switching too early can mean losing the calcium/phosphorus control that supports healthy skeletal development during their extended growth period. For small breeds, the risk of switching a bit early is lower since their growth window is shorter.

Do I need a large-breed puppy formula?

If your puppy is expected to exceed roughly 25 kg (55 lb) as an adult, a large-breed puppy formula with controlled calcium and phosphorus is generally recommended by veterinary guidelines to reduce the risk of developmental orthopedic issues.

How do I transition the food itself?

Mix increasing proportions of the new food with the old over 7-10 days to minimize digestive upset, regardless of which direction you're switching.

Puppy Food vs. Adult Dog Food: When to Make the Switch | PetCalculator

Puppy food and adult food aren't interchangeable -- the timing of the switch depends heavily on your dog's expected adult size. Here's how the two formulas differ and when to transition.