How To Help A Puppy Who Isn’t Gaining Weight

By Paula Fitzsimmons

You’re feeding your puppy a nutritionally-balanced diet and following the directions on the label with precision. You watch as your new best friend voraciously eats his dog food, and surmise his appetite isn’t the problem. Despite your best efforts, however, he’s not gaining weight as he should. Puppies grow at different rates, but if yours is below the average for his breed, there may be an issue. Anything from ineffective feeding methods to underlying diseases can cause slowed growth in puppies, says Dr. Dan Su, a clinical nutrition resident at the College of Veterinary Medicine at the University of Tennessee in Knoxville.

You may unwittingly be feeding your puppy an insufficient number of calories or a diet that lacks essential nutrients for growth. However, “medical causes of slowed growth are more common and can include parasites, digestive issues (such as inflammatory bowel disease), a liver shunt, and diabetes, for example,” Su says.

Read on to gain insight into why some puppies are resistant to weight gain, as well as what you can do to tip the scale in their favor. Of course, run any changes you plan to make to your puppy’s diet past your veterinarian first.

Underlying Causes 

For pampered pets, the inability to gain weight is rarely due to inadequate food intake, “especially if the puppy’s appetite seems good,” says Dr. Cailin Heinze, a veterinary nutritionist at Cummings School of Veterinary Medicine at Tufts University in North Grafton, Massachusetts.

It’s best to play it safe and bring your puppy to the vet to rule out medical causes. There could be any number of reasons behind her inability to gain weight, but intestinal parasites—particularly roundworms and hookworms—are probably the most common, says Dr. Joe Bartges, professor of medicine and nutrition at the College of Veterinary Medicine at the University of Georgia in Athens.

Inflammatory bowel disease, protein losing enteropathy (any condition of the GI tract resulting in loss of protein), and hypoglycemia are examples of diseases your vet may look for, says Dr. Susan Jeffrey, a veterinarian with Truesdell Animal Hospital in Madison, Wisconsin. Or the problem may be dental-related. “Is there something painful? For example, the puppy’s teeth may not have erupted normally and may be coming into contact with the tongue.”  

Additionally, certain foods can be too rich for some puppies and result in diarrhea. “This isn't necessarily a food allergy, but I think some pups with developing gastrointestinal tracts can't handle certain foods,” she explains.