How To Help an Underweight Dog Safely Put on Weight

Diamond's Friends Pet Rescue
Jun 9
5 min read

If you just adopted a dog who is underweight, you are likely wondering how you can help them get to a healthy weight.

Helping an underweight dog gain weight safely takes a mix of good nutrition, consistency, and sometimes a little veterinary support.

Here’s how to get your dog to a healthy weight so they can live their best life.

How To Tell if Your Dog is Underweight

Veterinarians use something the body condition score (BCS) to assess a dog’s weight. This scale ranges from one (emaciated) to nine (obese), with four to five being ideal.

You can do a quick check at home. If you see the following, your dog may be underweight:

Evidence of bony prominence
Loss of muscle mass
No discernible body fat
Pelvic bones visible or protruding
Visible ribs with no palpable fat

Learn More: At-Home Health Checks for Dogs

What Causes a Dog To Be Underweight?

Many things can cause your dog to be underweight, including:

Age
Expending a lot of energy
Insufficient or poor diet
Stress or anxiety
Underlying health issues

If you just adopted your dog, there is a chance that they have come from a more difficult background where food was not readily available or offered regularly.

How To Help Your Dog Gain Weight Safely

There are some key steps to follow if you want to help your dog gain weight safely. Weight gain won’t (and shouldn’t) happen overnight. But if you follow these steps, you should have your dog on the path to a healthy weight soon.

1. Start With a Vet Visit

The first thing you want to do before starting to help your dog put on some weight is visit your vet. They can help give you a target weight range and rule out any underlying issues that could be causing your dog’s lack of weight.

Issues that can impact a dog’s weight include:

Dental issues
Diabetes
Infection
Kidney or liver disease
Malabsorption issues
Parasites
Thyroid issues

Your vet may even be able to suggest some appropriate food for you to feed your dog. Which brings us to step two…

Learn More: How To Choose a Veterinarian

2. Feed a High-Quality, Calorie-Dense Diet

According to Purina, you’ll want to choose a dog food that is:

Contains high levels of key nutrients
Has lots of protein
Includes plenty of calories
Nutritionally balanced

You can also look for:

Highly digestible formulas
Formulas that are appropriate for your dog’s life stage

Try to avoid simply giving higher amounts of low-quality kibble. It may be full of fillers with little nutrition.

Also, don’t just start giving your dog people food to try to help them put on the pounds. Not only are some of the foods we eat toxic for dogs, but people food generally won’t have the right nutritional components to help your dog gain weight safely.

Learn More: How To Choose the Right Food for Your Dog

3. Feed Smaller Meals More Frequently

If you are dealing with an underweight dog, they may not be used to one or two large meals during the day. To help them get enough nutrients to get to a healthy weight, Purina recommends giving them three or four smaller meals throughout the day.

This strategy can be easier on their stomach and help them maintain a steady calorie intake.

Pro tip: Consider using slow feeders if your dog is not used to having access to food so that they don’t eat too fast and get bloat.

4. Add Healthy Toppers (Especially if You’re Dealing With a Picky Eater)

To give your dog some extra calories or to help encourage a picky eater to eat all their meals, you could add the following to their food:

Boiled chicken, salmon, or turkey
Canned dog food
Dog-safe bone or chicken broth
Dog-safe peanut butter (xylitol-free, in moderation)
Plain cooked rice or sweet potatoes
Scrambled eggs with no seasoning

These can add calories without sacrificing nutrition.

Learn More: Foods That Are Toxic To Dogs

5. Use Supplements Wisely

Beyond Pets suggests considering supplements but using them wisely. Ask your vet before incorporating these into your dog’s diet.

Supplements that may help include:

Omega-3 fatty acids (like fish oil) support skin, coat, and weight gain
Probiotics to help with digestion and absorption of nutrients
Weight-gain powders

6. Give Treats (in Moderation)

Treats can help give your dog some extra calories, but don’t give them a whole meal of treats each day. You want to make sure your dog is getting proper nutrients through quality food.

Your dog won’t get adequate nutrition through treats alone.

7. Keep Exercise Balanced

Continue to give your dog exercise in moderation. The goal of exercise should be to stimulate your dog’s appetite and build muscle mass.

You’ll want to avoid exercising your dog to the point where they burn more calories than they consume. Short, fun walks and gentle play are ideal.

8. Track Progress Each Week

It’s essential to track your dog’s progress regularly to make sure they are moving toward a healthy weight. Making sure they are moving toward the four or five range on the BCS scale is important.

If you have a scale, you can do weekly weigh-ins to make sure your dog is putting on some pounds. If your vet gave you a target weight range, this can help you numerically track your dog’s progress.

Keep in mind that the goal isn’t to get your dog up to their ideal weight quickly. This is a gradual process that will take time depending on how underweight your dog is.

When To Be Concerned

So, when should you start to be concerned about your dog’s weight? If you are doing all of the following and your dog:

Can’t keep food down
Doesn’t gain weight after two to three weeks
Loses weight despite eating well
Shows signs of digestive upset or lethargy

It’s time to consult your vet again. Something could be seriously wrong, and you’ll need your vet’s help to figure it out.

Final Thoughts

Adopting an underweight dog is rewarding, but it can be stressful as you work to get them to a healthy weight. Be patient. Safe weight gain in dogs is a slow, steady process.

Disclaimer: This article is not intended as professional medical advice. It is based on personal experience and online research. Please consult with your veterinarian if you are concerned about your dog's health.