Diet plays an important role in the endurance potential of canine athletes. The Alaskan sled dog might be considered the ultimate canine athlete, sometimes pulling a sled more than 1,000 miles in subzero temperatures. Providing a well-balanced diet is essential to meet the special needs of dogs in such nutritional-stress situations. Not only should the diet fed to these dogs be high in protein, but it also should be high in fat, which serves as the major energy source for exercising muscles.
A high-fat diet can help muscles burn fat more efficiently. During sustained exercise, fatty-acid oxidation is the primary source of energy for the muscles. Increasing the efficiency of fat metabolism spares the body’s use of carbohydrates, and because most dogs have in excess of 10 to 50 times more energy stored in fat than in muscle glycogen (carbohydrate), this might boost the animal's exercise performance.
IAMS™ studies1 have shown that in trained sled dogs as in ordinary dogs, exercise performance was enhanced by switching from a low-fat to a high-fat diet (from 25 to 65% of calories from fat), as indicated by increased:
When dogs were switched back to a low-fat diet, all of these criteria decreased to their previous values.
These results indicated that by increasing the availability of fat stores and capacity to metabolize fat for energy, a high-fat diet promotes exercise endurance in canine athletes.
1 Reynolds AJ, et al. “The effect of diet on sled dog performance, oxidative capacity, skeletal muscle microstructure, and muscle glycogen metabolism.” Recent Advances in Canine and Feline Nutritional Research: Proceedings of the 1996 IAMS International Nutrition Symposium. Carey DP, Norton SA, Bolser SM, eds. Wilmington, OH. 1996. 181–198.
Dogs are as unique as people, but despite their differences, they all need a well-balanced diet for good health. However, dogs of different ages and sizes have different nutritional needs, and this is especially true for puppies. When you factor in developmental needs, ingredients and your puppy’s size and breed, choosing the right food can be difficult.
The energy requirements of a puppy can be nearly twice those of an adult dog. This means that a puppy might not have the stomach capacity to eat enough food to meet his needs unless the food is specially formulated.
When choosing a puppy food, select one that provides a highly digestible, nutrient-dense, 100% complete premium formula for growth. Such high-quality formulas contain the vitamins, minerals, protein, fat and carbohydrates your dog needs for sound and healthy development. With a premium formula, your puppy may have:
Puppies grow fastest during the first six months of life, and because growth rates differ among breed sizes, you need a formula designed to address the needs of your puppy’s breed or size. Feed your puppy this formula based on the recommended amounts for his weight and age until he is an adult.
Although large-breed dogs have bigger bones than medium or small breeds, large-breed puppies do not need more calcium. University studies have shown that:
Overfeeding and weight gain can contribute to developmental bone problems. This makes managing food intake even more critical. Puppies are at greater risk for developmental bone problems if they are overfed.
A formula with reduced fat and calories promotes optimum growth. Controlling the rate of growth to promote normal development is another reason to feed a large-breed diet, such as IAMS™ ProActive Health™ Smart Puppy Large Breed.
Medium-breed puppies have needs between those of large- and small-breed dogs. A medium-breed puppy’s nutritional demands can be satisfied by feeding a 100% complete and balanced formula that features moderate amounts of all the essential vitamins and nutrients, such as IAMS ProActive Health Smart Puppy Original.

Small-breed puppies have unique needs due to their small mouths and small stomachs, as well as the rapid growth spurt they experience when growing to adult size. That’s why it’s important to pack a lot of nutrition and energy into a small amount of food. A poor-quality diet might fill a puppy’s stomach before he can eat enough food to satisfy his nutritional needs. The result can be improper muscle and skeletal development and growth impairment.
IAMS™ puppy foods are formulated to be energy- and nutrient-dense to meet the needs of growing puppies. The IAMS™ formula for small and toy puppy breeds, IAMS™ ProActive Health™ Smart Puppy Small & Toy Breed, has concentrated nutrition for the lifelong health of your small- or toy-breed dog.