Underweight Boxer Dog.

How To Fatten Up Your Dog In A Healthily: Fact Checked By Our Vet

Written By Vedrana Nikolic | Canine Coach, B.A Ethnology & Anthropology, M.A Semiotics.
Edited & Fact Checked By Renae Soppe | B.A Journalism & Science. 
Last Updated: 9th January 2024

Obesity in dogs seems to be getting more and more common. This is a problem that’s often talked about, although the talking does not seem to help.

What is talked about much less underweight dogs, although that’s a valid problem too. If you’ve found yourself asking “how to fatten up my dog?”, today’s guide is an attempt to help you.

How to Put Weight on a Dog: The Top Tips

#1 Don’t Do Anything Dramatic

Before we move on to the other tips to help your dog gain weight, we have to start with a disclaimer. The most important thing is not to do anything dramatic!

Dogs don’t respond well to sudden changes in their diet of any kind. Everything needs to be done gradually and with patience, whether it’s increasing the amount of food you are feeding or introducing a new type of food to their diet.

So, whatever you do, do it gradually. Introduce changes slowly over time and have patience. Trying to rush things will not work.

#2 Just Offer More Food

Well, if you’ve been trying to fatten up your dog, you might have already tried this. But still, it might be worth saying. Sometimes all it takes is just increasing the daily amount of food you give to your dog.

You don’t have to stick to the recommended amounts on dog food packaging religiously. These are just guidelines.

“You must remember that each dog is an individual and their body structure and metabolism is unique to them. For example, dogs that are working dogs have a higher metabolism (more muscling and activity) and are burning more calories than a dog sleeping on the sofa. They need more calories to maintain weight.” - Dr. Beth Turner, Preventive Vet (1)

So, don’t be afraid to experiment and stretch those guidelines to fit your dog. Many pet parents find that their dogs need to eat less than the recommended amount.

In the case of my dog (a moderately active female Staffy mix), it’s the opposite. All her life she has been eating slightly more than the recommended amount + treats to maintain a healthy weight. When we tried the recommended portions, she ended up being way too skinny. Unusual, but it happens.

#3 Increase the Number of Meals

Offering food multiple times per day might be the way to get your pooch to eat more (and gain more weight from the food they eat). While there is a belief (and even some proof) that adult dogs should eat only once per day, eating 2 or 3 meals in a day might work better for your pup.

“Feed multiple small meals throughout the day rather than one or two larger portions. Dogs will typically eat more under these conditions” - Jennifer Coates, DVM, PetMD (2)

You might even let your dog graze and eat as much food as they want whenever they want, but that won’t work for everyone. It also might prove difficult to change this habit later when your dog is not underweight, so be careful about that one.

Related: How Many Times A Day Should You Feed Your Dog?

#4 Go All Out With the Snacks

Snacks are an easy way to boost your dog’s calorie intake. They work just like snacking for humans. By eating a little bit all the time, your pooch is sure to gain weight. Even more, if you choose high-calorie snacks.

Things like dry meat or fish pieces or even something like cheese or peanut butter can be a great high-calorie snack. But really, any kind of snack or treat will work. Go ahead and give extra rewards to your dog when they exhibit desirable behaviours. If you are trying to get them to gain weight, it’s a win-win situation.

#5 Offer High-Calorie Foods

This is another tip that might be a bit obvious, but make sure you offer your dog calorie-dense foods. This is a surefire way to help healthy dogs gain weight.

Related: The Best Dog Food Australia
Related: How To Choose The Right Dog Food?
Related: Understanding Guaranteed Analysis Levels in Dog Food
Related: Real Meat vs Meat Meal

And that means food that contains lots of protein & fat. Dogs need lots of protein in their diet, but there is no need to go over the top since there is such a thing as too much protein. Foods that are high in fat are great, because fat is the most calorie-dense form of nutrition, and there is pretty much no downside for dogs:

“One common myth about fat and pets is that high-fat diets can cause heart disease. High-fat diets, especially those high in saturated fat, have been associated with clogging of arteries and heart attacks in people. However, healthy dogs and cats do not get this kind of heart disease, so there is no need to restrict fat to prevent it.” - Cailin R. Heinze, Petfoodology (3)

Keep in mind: While protein & fat are generally good, carbs are not. Getting your dog fat by feeding lots of carbs might work, but this is not a healthy way to help your pooch bulk up.

You might choose to switch your dog to some of the high-calorie foods for dogs you can buy (often geared towards working dogs), or include some calorie-rich additions into your dog’s regular diet.

“Human” food which dogs can eat, to help boost their calory intake include cheese, eggs, all kinds of meat, fish, and even peanut butter (in moderate quantities).

#6 Switch It Up

This tip is relevant for picky eaters only: offer them novelty. Some dogs are just so picky that they will start starving themselves.

These dogs often have preferences and won’t eat just any kibble you throw at them. Even worse, they sometimes seem to change their minds and stop eating what was their favourite food yesterday. In such cases, offering a new type of food every once in a while might be what’s needed to keep the dog interested.

Adding tasty toppers to their regular food might also be a good choice.

#7 Don’t Forget the Exercise

Don’t let your dog lounge around all day in hopes it will help with the weight gain. Yes, being lazy might help your dog fatten up faster, but that’s not the right way to go.

Underweight dogs often need to build muscle mass too. And there is no other way to do it than to get regular exercise.

Feeding Previously Starved Dogs: Things to Keep in Mind

So far, we’ve talked about helping your dog to gain weight, but we didn’t consider the reason why your dog might be underweight. There could be many reasons for this, and we’ll talk about that in a minute, but sometimes the reason can be quite obvious.

Sadly, it’s somewhat common to encounter rescue dogs who are underweight as a result of neglect and starvation. When we see such a dog, our instinct might be to offer them all the food in the world. However, this can be dangerous!

There is something called “refeeding syndrome”. Namely, the digestive tract of a starved animal can end up going into shock of sorts if it suddenly has to deal with large amounts of food. To prevent this, it’s important to start slowly and feed smaller amounts of food in the first couple of days to help the dog get used to the new regime. (4)

Is Your Dog Underweight?

On the other hand, it’s also a common occurrence that pet parents believe their dogs should be fatter than they need to be. Some dogs are naturally skinny and may appear underweight when they aren’t.

For example, being able to feel your dog’s ribs and, with some breeds, even seeing a faint outline might be completely normal.

So, before you get on a quest to fatten up your dog, make sure that you understand what their ideal weight should be. You can use something like the PetMD healthy weight tool to help you get an idea, but the easiest way is definitely to ask your vet for an opinion during your next visit.

My Final Thoughts

Keeping your dog at an optimal weight is pretty important. Being overweight can be the cause of a variety of health problems in dogs, but being underweight is not much better. One thing to keep in mind is that being underweight can also be a symptom of an underlying problem.

Related: How Is Australia’s Dog Food Industry Regulated?
Related: What is AAFCO? The Association of American Feed Control Officials
Related: What Is the Pet Food Industry Association of Australia (PFIAA)?
Related: AAFCO vs PFIAA: Dog Food Standards Comparison Australia

If you tried changing your dog’s diet and upping the calorie intake, but the dog doesn’t seem to be gaining any weight, it might be time to get worried. There is a whole range of things that could be causing this: from stress to pain to parasites to some form of serious illness, like thyroid conditions, diabetes, or even cancer. So, in the end, if you can’t see any logical reason why your dog isn’t gaining weight, or they suddenly start losing weight, make sure to talk to your vet about it. It could be a sign of something serious.


  1. Turner, B. February 22, 2021. “How Much and How Often Should You Feed Your Dog?”. Preventive Vet. Retrieved December 13, 2022. https://www.preventivevet.com/dogs/how-much-and-how-often-to-feed-your-dog
  2. Coates, J. December 10, 2019. “What’s the Best Dog Food for Weight Gain?”. PetMD. Retrieved December 13, 2022. https://www.petmd.com/dog/nutrition/whats-best-dog-food-weight-gain
  3. Heinze, C. R. March 15, 2018. “The Skinny on Fat: Part 1 – The Basics”. Tufts Petfoodology. Retrieved December 13, 2022. https://vetnutrition.tufts.edu/2018/03/the-skinny-on-fat-part-1/
  4. Coates, J. October 4, 2013. “Feeding the Starving Dog”. PetMD. Retrieved December 13, 2022. https://www.petmd.com/blogs/nutritionnuggets/jcoates/2013/oct/the-right-way-to-feed-dog-that-has-been-starved-30937

Vedrana Nikolic

Vedrana Nikolić is Gentle Dog Trainers Canine Coach, Professional Writer, Anthropologist & dog lover.

With a Masters Degree in Semiotics & Bachelors Degree in Anthropology, studying the communication between animals and humans, Vedrana is able to use her expertise to analyse and review dog products and write informative posts on canine behaviour and training.

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