Dr. Pascale Pibot
Royal Canin Research Center
Owners are often tempted to switch their puppies very early to adult food: they do that for economical reasons, because they underestimate the duration of growth, or because they falsely think that "too-rich-puppy food" could be harmful to growth. It is important to keep in mind how different the puppy's nutritional requirements are compared to adults. These special requirements justify a specific food until the end of the growth.
Energy Requirements
During the first half of its growth, a puppy needs twice as much energy than an adult, compared to its bodyweight. This multiplier coefficient decreases progressively, but when the puppy reaches 80% of its adult bodyweight, it still consumes 20% more energy than an adult. Feeding him with a concentrated puppy food avoids overloading its digestive tract.
Puppies have very different growth rates according to size.
- A small-breed puppy reaches 40 - 50% of its adult bodyweight within about 3 months, a large-breed puppy not before 5 months.
- A toy Caniche reaches its adult bodyweight within about 8 months: at that point, it has multiplied its birth weight 20 fold. A Newfoundland puppy still grows up until 18-24 months, until it has multiplied its birth weight about 100 fold.

Protein Requirement
A puppy requires a great amount of protein for the synthesis of the skeleton and all other tissues. Its amino-acid requirement is then far more important than for an adult. In addition, a puppy does not use proteins as efficiently as an adult. To make up for this less efficient digestive capacity, a growth product must contain at least 25 - 30% more proteins than a maintenance adult product. In a puppy, a protein deficiency may induce: delayed growth, immune system weakness, anemia, etc …
Mineral Requirements
Since large breed puppies are susceptible to growth abnormalities if fed a diet too high in calcium, feeding the correct puppy formula is important for their long term health.
Starch Digestion
The production of enzymes that digest starch (amylases) reaches an optimum level only when the puppy has completely achieved its growth. Before, a puppy does not digest starch as well. A maintenance adult diet can contain up to 50% starch, but a puppy food should not contain more than 30% starch. Feeding an adult diet to a puppy can induce loose stools, diarrhea, and possibly favor coprophagic behavior (eating their own stools).
Adaptation to the Breed's Size
All puppy foods have some common characteristics: high energy density, concentration of all essential nutrients, and a decrease in starch level. But the size of the breed implies specific adaptations.
- Large-breed puppies are much more likely to suffer from skeletal growth diseases. These troubles are exacerbated by an over consumption of energy, accelerating the growth, as well as too high a level of dietary calcium. Limitation of the fat content and controlling the level of calcium in the food is the best way to minimize the risks.
- On the contrary, small and medium-breeds puppies must receive a lot of energy, but in a small volume. They require a more concentrated diet.
Conclusion
A puppy product is not used during the same time according to the breed: 8 -10 months for small breed puppies, 10-12 months for medium, and 14-18 months for the larger breeds. Pet owners should wait until the end of growth before switching their puppy to an adult product. There is no disadvantage to feeding a puppy food longer than initially planned, provided the bodyweight of the dog is not excessive.