How to Put Weight on an Underweight Dog

By Betty Lewis

Most everyone likes the idea of shedding some weight, however weight loss isn't always welcome. If your dog is underweight, you're right to want to get him back up to a healthy weight. It may be as simple as adding a bit more to his food dish or switching foods. If there's a medical reason for low weight, your vet should address the reason behind his thinner form before you can put weight on him.

Ideal Body Weight

You may know your dog is underweight because you monitor his weight via the scale. If you don't have a scale, you can tell if your dog's at a proper weight level with your eyes and hands. The Nestle Purina Body Condition System is a quick way to gauge if a dog is at a healthy weight. At his ideal weight, your dog's ribs should be easily felt with minimal fat covering and his waist should be distinguished if you view him from above. If he's underweight, you'll be able to see and feel his ribs, and his pelvic bones will be visible.

Reasons for Weight Loss

If you want to put weight back on your dog, you need to understand why he's underweight. There are a variety of reasons a dog may lose weight, ranging from mild, routine medical conditions to more serious illnesses. Common reasons for weight loss in dogs include:

  • Poor quality diet.
  • Excessive physical energy or extended exposure to cold causing him to burn more calories than he consumes.
  • Malabsorption or digestive disorders.
  • Hypermetabolic state.
  • Anorexia, swallowing disorders or regurgitation causing anorexia.
  • Diarrhea, vomiting or excessive urination causing the loss of too many nutrients.
  • Change in diet.
  • Stress or a change in routine.
  • Routine aging.

Common diseases associated with weight loss in dogs include liver disease, kidney failure, cancer and periodontal disease.

Veterinary Attention Necessary

If your dog has lost a little bit of weight, it's time to pay attention to him, his eating behavior and activity level. Perhaps the weather has turned and you've been out and about more recently, meaning he's burning more calories. If that's the case, a little extra food in his bowl will make up for the extra energy he's burning, or you can cut back on his exercise. However, if you notice your dog's been lethargic, uninterested in food or that he's lost more than 10 percent of his body weight, he should see his vet. The vet will consider your dog's symptoms, medical history and perform an exam that may include a stool sample, bloodwork and other tests such as radiographs.

Strategies for Gaining Weight

If there's a medical reason for your dog's weight loss, treating the underlying cause will facilitate weight gain. However, sometimes more than medical treatment is necessary to help pack on a few extra ounces -- or pounds. When a dog is anorexic and has no obvious medical condition causing his low weight, you'll have to be creative to encourage him to eat.

A change in diet, particularly if the dog hasn't been eating optimally, can make a big difference. Your dog may have decided he doesn't care for what you've been offering or that he prefers what comes off your plate. Adding canned food to his dry food, or switching to a diet of canned food may be a simple way to put on some extra weight. Canned food is frequently used to help dogs gain weight because the odor is enticing to dogs, prompting them to eat. Your vet can help by prescribing appetite stimulants to make him eat more or a prescription food that will help fill him out. High calorie pastes and gels are available in pet stores.

A higher calorie food, such as puppy food, can provide your dog the extra calories he needs to put on weight. Allow him to free feed, or offer him several meals a day. Some extra treats throughout the day also can provide him an enjoyable calorie boost.

Emaciated Dogs

A severely malnourished and underweight dog requires special consideration as well as veterinary oversight. It's natural to want to feed an emaciated dog as much as he'll eat because he looks, and is, starved. However, overfeeding a starved dog can result in serious consequences, including refeeding syndrome. An emaciated dog should be fed a small meal every six hours, as well as a broad-spectrum vitamin and mineral supplement. A meat-based, highly digestible growth food, such as puppy food, is ideal for putting weight on an emaciated dog.

Discuss your dog's ideal weight with your veterinarian. The vet can work with you to determine how much food your dog should eat based on the food, your dog's health, age and exercise level.