The All You Need to Know Guide to Healthy Weight Gain for Dogs

Much like humans, weight gain for dogs isn’t just about calories—age, metabolism, health and lifestyle and activity levels all play a role. With thoughtful feeding and a focus on nutrient-dense foods, you can help your dog gain weight healthily and sustainably, ensuring they thrive for years to come.

You wouldn’t stuff yourself with junk food to gain weight, right? Dogs deserve the same thoughtful approach. In this blog I share reasons that your dog could be underweight, signs that your dog may not be their ideal weight, and lots of strategies and healthy food ideas to help your dog pile on those extra pounds and increase weight healthily.

Maintaining a healthy weight in dogs is about far more than appearance—it’s vital for their overall health and longevity. In fact, research from Banfield Pet Hospital [1] suggests that dogs at an ideal weight can live up to 2.5 years longer. That’s extra years filled with walks, playtime, and adventures.

Being underweight can significantly affect a dog’s overall well-being in several ways, impacting both their physical health and emotional state. Here are some key reasons why being underweight can be detrimental to a dog’s health:

Being underweight can have serious consequences for a dog’s well-being, impacting both their physical and emotional health. Here’s why:

1. Weakened immune system

A lack of proper nutrients weakens a dog’s immune system, making them more susceptible to infections and illnesses. Malnourished dogs are more prone to infections due to reduced immune function.

To learn more about the essential role of your dog’s immune system check out Dr Katie Woodley’s blog, The Basics of Dog Immunity.

2. Loss of muscle mass

Underweight dogs often lose muscle mass, which affects their strength and mobility. This can lead to decreased physical activity and overall fitness.

3. Low energy

Without enough calories, underweight dogs are frequently tired and lack energy. This reduces their ability to exercise and can lead to further weight loss.

4. Poor skin and coat health

Insufficient nutrition can lead to a dull, brittle coat, dry skin, and conditions such as dog dandruff increasing the risk of skin infections and discomfort.

5. Increased injury risk

With less fat and muscle to cushion their body, underweight dogs are more vulnerable to injuries such as fractures and sprains.

6. Digestive issues

Dogs that are underweight may suffer from malnutrition, which can exacerbate existing digestive issues or create new ones. Problems like dog vomiting, diarrhoea, or nutrient malabsorption can make it even more difficult for them to gain weight and receive the nourishment they need.

7. Emotional and mental health

Just like humans, dogs can experience stress and anxiety from physical weakness. If their body isn’t receiving the nourishment it needs, they may become anxious, depressed, or irritable, affecting their emotional well-being and behaviour.

The link between diet, mood, and behaviour is now widely recognised. To learn more, check out Anna Bain’s article, The Hidden Influence of Nutrition on Your Dog’s Mood, where our canine nutritionist writer dives deep into how what your dog eats affects their emotional well-being.

For some dogs, it’s easy to tell they’re underweight—they look visibly skinny. But for others, it’s not as obvious. Here are a few key signs that can help you determine if your dog is underweight:

• Visible ribs, hips, and spine

• Low energy levels, lethargy, or even signs of depression

• A dull, dry, or shedding coat

• Consistent poor eating habits

Weighing your dog

Weighing your dog can be a great starting point to check if they’re in a healthy range. Each breed has a typical weight range, but individual dogs can vary based on factors like age, activity level, and metabolism. To get an idea of your dog’s ideal weight, you can use ProDog’s Breed Weight Search tool or consult your vet for a more personalised approach.

Most vet clinics and some pet stores have scales you can use. If your dog is small enough, you can weigh them at home: step on the scale without your dog, then step back on while holding them. The difference between the two weights is your dog’s weight.

The better method: Body Condition Scoring (BCS)

While weighing is useful, Body Condition Scoring (BCS) is my preferred method for assessing a dog’s ideal weight. The beauty of BCS is that it focuses on your individual dog’s body composition, rather than relying solely on breed guidelines, which can vary.

BCS uses a scale from 1 (emaciated) to 9 (obese), with an ideal score falling between 4 and 5. You should be able to feel your dog’s ribs without seeing them. If your dog scores below 4, it’s time to take action.

Check out the BCS chart below, and watch expert vet Dr Nick Thompson’s video, where he breaks down exactly how to assess your dog’s body condition.

Weight loss happens when a dog burns more calories than they consume, but it’s far from that simple. Factors like age, metabolism, health and activity level, and even breed all impact how your dog manages weight. Understanding the cause of their weight loss is the first step to finding the right solution.

Here’s what could be contributing to your dog’s weight loss:

Age & activity levels

Puppies are growing rapidly and have faster metabolisms, so they need more calories to fuel their development. In contrast, senior dogs often slow down and require fewer calories as their metabolism decreases and activity levels drop, making it easier for them to lose weight unintentionally if not carefully monitored.

For more guidance on caring for your older dog, check out How to Support the Health of Senior Dogs Naturally. If you’re a new puppy parent, our Puppy Raw Feeding Guide and Welcoming a New Puppy guide, written by canine behaviourist Caroline Spencer, are both excellent starting points.

Neutering/spaying

Neutering or spaying can reduce your dog’s metabolic rate by altering hormone levels, which in turn slows down calorie burn and can reduce appetite. Dogs often need dietary adjustments post-surgery to avoid weight gain or weight loss and to manage any potential fluctuations. The hormone fluctuations experienced by unspayed and unneutered dogs means some may go off food entirely and stop eating at certain times, resulting in too much weight loss.

Medical issues

Diarrhoea, vomiting, excessive urination

These symptoms can lead to nutrient loss and dehydration, making it harder for your dog to maintain or gain weight. Chronic cases often result in significant weight loss if left untreated.

Dental problems or loss of smell

Dogs with dental issues or a loss of smell may struggle to eat, reducing their caloric intake. Pain from chewing or difficulty sensing food makes meals less appealing, which directly impacts weight.

Inflammatory bowel disease or exocrine pancreatic insufficiency

Both conditions affect nutrient absorption. With inflammatory bowel disease (IBD), inflammation in the intestines hinders nutrient uptake, while exocrine pancreatic insufficiency (EPI) prevents proper digestion, leading to malnutrition and weight loss even if the dog eats well.

Metabolic disorders like diabetes, hyperthyroidism, or cancer

Metabolic conditions like dog diabetes or hyperthyroidism alter how the body processes energy. Hyperthyroidism speeds up metabolism, causing rapid weight loss, while diabetes can interfere with insulin regulation, affecting nutrient use. Cancer can also cause unexplained weight loss due to increased metabolic demands or loss of appetite. Kidney issues or renal failure can affect the appetite of dogs, and one of the first signs of kidney issues is weight loss.

Stress & anxiety

Stress and anxiety can trigger appetite suppression in dogs, making them disinterested in food. Major life changes, separation anxiety, or environmental stressors can significantly impact their eating habits and lead to weight loss.

Fussy eaters

Some dogs are naturally picky, refusing to eat certain foods or only consuming small amounts. These dogs may require tailored, higher-calorie meals to meet their nutritional needs and prevent weight loss due to insufficient calorie intake. Caroline Spencer Canine Behaviourist shares her unique method to Helping Fussy Dogs Eat in her guide.

An important note I need to make here is that when navigating the root cause of your dog’s weight management issue it’s always important to consult a vet to rule out underlying health conditions.

Weight management comes down to balancing calories in versus calories out, but as already discussed other factors like age, breed, lifestyle and metabolism play significant roles too.

When helping a dog gain weight, it’s not just about calories; it’s about nutrient density. Protein, fats, and carbohydrates all play important roles in ensuring that your dog gains weight in a healthy way. Feeding a more calorie-dense, nutrient-rich diet is essential to support their recovery and long-term health.

Protein is the cornerstone of muscle development, so you’ll want to focus on high-quality, minimally processed sources such as lightly cooked fresh meats or raw dog food meals with higher fat content like beef, lamb, and duck.

There is much evidence supporting the benefits of high-protein diets, particularly raw diets, in improving muscle mass in dogs [2]. Studies on performance dogs, such as sled dogs and racing greyhounds, have shown that diets rich in protein and fat improve muscle maintenance and overall physical endurance.

High-protein raw diets help promote lean muscle mass and improve nutrient absorption, both of which are crucial for active and working dogs and also for dogs requiring weight gain.

Amino acids: the building blocks of protein

Amino acids, the components of protein, play a crucial role in supporting all aspect of your dog’s health, including gut health particularly when it comes to healing and maintaining the digestive lining. Ensuring that your dog receives high-quality protein is essential not only for overall repair but also for ongoing gut support.

While humans require eight essential amino acids, dogs need ten. These essential amino acids are: Arginine, Histidine, Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Threonine, Tryptophan, and Valine. Dogs primarily obtain these amino acids from the meat in their diet. Although some amino acids can be found in plant sources, meat provides a far more reliable and complete source for dogs.

What do I mean by ‘quality’ protein? It’s important to note that the processing methods of many commercial pet foods, such as kibble, processing methods, can compromise the quality of these amino acids. This is why some processed foods include additional synthetic nutrient supplements to compensate.

Incorporating raw meat into your dog’s diet ensures they get the necessary building blocks to support muscle growth, immune function, and gut health in the most effective way possible.

Our Raw Dog Food For Beginners is the ideal introduction to raw feeding dogs.

Including healthy fats in your dog’s diet is essential to weight gain. Whether your dog is underweight due to illness, age, or metabolic issues, adding nutrient-rich fats like oily fish, whole eggs, coconut oil, and animal fat ensures that they receive the extra calories needed for healthy weight gain, along with essential nutrients that benefit their skin, coat, metabolism, and overall vitality.

Healthy fats are a critical part of a balanced diet for the majority of dogs, especially when it comes to helping underweight dogs gain weight in a safe and effective way. Fats are not only the most calorie-dense nutrient, providing more than twice the energy of proteins and carbohydrates, but they also play essential roles in supporting overall health.

Calorie-dense energy source

Fats are the most concentrated source of calories available in the diet. Each gram of fat contains approximately 9 calories, compared to just 4 calories per gram of protein or carbohydrate. This makes fats an efficient way to boost your dog’s calorie intake without having to increase meal sizes dramatically, which is particularly helpful for dogs that struggle to eat large meals.

Supports muscle growth and tissue repair

Fats are essential for the absorption of fat-soluble vitamins (A, D, E, and K), which are crucial for maintaining muscle growth, skin health, and immune function. Vitamin E, for example, is an antioxidant that helps protect cells from damage and supports tissue repair, which is particularly important for underweight dogs trying to regain healthy body mass.

Promotes healthy skin and coat

One of the most noticeable benefits of healthy fats is their impact on a dog’s skin and coat. Essential fatty acids, such as omega-3 rich in foods such as oily fish, and omega-6, are key to maintaining skin elasticity and a shiny, healthy coat. A dog’s coat condition can deteriorate when they’re underweight or malnourished, and incorporating healthy fats can quickly help restore a dog’s appearance.

Regulates metabolism and hormonal balance

Fats also play a role in regulating metabolism and hormone production. The inclusion of good fats in a dog’s diet can help balance their metabolism, which is especially important if the dog has undergone neutering or spaying.

And the list goes on: Fats enhance meal palatability for picky eaters, making it easier to boost calorie intake. Omega-3 and omega-6 fatty acids reduce inflammation and support joint health, while DHA-rich fats promote cognitive function, especially in puppies and senior dogs, keeping their minds sharp [3].

For a complete low-down on fats for dogs check out my guide, The Truth About Fats For Dogs

The topic of carbohydrates in a dog’s diet often sparks debate. Due to their widespread use in commercial pet foods, many people assume that dogs require carbohydrates. The reality, however, is that dogs don’t have a biological necessity for carbs, as their ancestors thrived on a diet primarily composed of proteins and fats.

Many published studies reinforce this by showing that dogs and cats do not have dietary requirements for carbs [4], they thrive on carbohydrate-free diets as long as they get adequate protein and fat sources for energy .

That said, carbohydrates aren’t entirely without value. While dogs don’t need them, some dogs—especially those that are highly active, anxious, or reactive dogs—can benefit from small amounts of complex carbohydrates. Ingredients like cooked sweet potatoes and oats provide slow-releasing energy, offering a steady fuel source without causing rapid spikes in blood sugar and are soothing to the nervous system.

Additionally, small amounts of plant-based carbohydrates, such as fruits and vegetables, offer other benefits. These ingredients provide valuable micronutrients, including vitamins, minerals, and antioxidants, which help support overall health. Furthermore, plant-based carbs often contain prebiotic fibres that promote optimal gut health by nourishing beneficial bacteria in the digestive system.

So, while dogs don’t need carbs in the traditional sense, incorporating the right types of complex carbohydrates and plant-based sources in moderation can offer energy, gut health, and micronutrient support, all particularly important for dogs to gain weight.

I always encourage dog owners to get creative with their dog’s meals by incorporating real, nutritious food they already have in the kitchen. Many human foods are excellent for boosting your dog’s nutritional intake, but it’s important to be cautious—certain foods like onions, grapes, and raisins are toxic to dogs. For a comprehensive list of safe and unsafe foods, check out our A-Z Guide: What Can My Dog Eat?, your go-to resource for feeding your dog safely.

If it hasn’t been made clear yet, one of the most effective and natural ways to help your dog gain weight is through raw feeding. Raw foods are packed with bioavailable nutrients, meaning they are easier for your dog to absorb and utilise [5]. This can make a significant difference when you’re focusing on healthy weight gain.

When planning a raw diet for weight gain, aim for calorie-dense, high-fat meats like: tripe, beef, lamb, and duck if tolerable, and if your dog isn’t struggling with digestive issues.

If you’re new to raw feeding, our Switching Your Dog To Raw guide is a comprehensive resource that explains how to smoothly transition your dog from processed foods to a fresh, natural diet. Plus, companies like ProDog Raw make it easier than ever by delivering FEDIAF-compliant, nutritionally balanced raw dog food meals directly to your door.

Incorporating raw foods into your dog’s diet is a powerful step towards helping them achieve a healthy weight, with the added benefit of supporting overall health and well-being.

When your dog needs to gain weight—whether recovering from illness, dealing with muscle loss in old age, or simply being a picky eater—supplements can be a valuable tool. They provide targeted support that helps fill nutritional gaps and promote healthy weight gain. If you’re new to the world of dog supplements, our Beginners Guide to Dog Supplements is an excellent place to start. But for now, here’s a breakdown of key supplements that can assist with weight gain:

1. Muscle-Building Supplements

For dogs needing extra help building muscle mass, protein-rich supplements are a great solution. Muscle gain supplements support the development of muscle mass, which is essential for both weight gain and overall strength.

It’s crucial to avoid supplements loaded with fillers and artificial ingredients. Instead, look for products like ProDog’s dog supplement range, which is vet-approved and contains only active ingredients. This ensures that every component provides nutritional benefits, without unnecessary additives.

ProDog’s Muscle + weight gain protein powder for dogs is an excellent choice, with 76% high-quality protein in every scoop, it’s a simple way to incorporate more quality protein and is formulated by canine nutrition experts to support muscle growth in a healthy and balanced way.

2. Digestive Enzymes

Digestive enzymes play an essential role in breaking down food so your dog can absorb nutrients efficiently. If your dog is struggling to gain weight due to digestive issues, adding enzymes can improve digestion and ensure they get more out of every meal.

Supplements like ProDog Raw’s Digest, dog gut health supplement, can be highly effective in enhancing nutrient absorption, particularly in dogs with sensitive stomachs or digestive disorders. Healthy digestion is critical for optimal weight gain, as it ensures that your dog is receiving the full benefit of their diet.

3. Probiotics

Probiotics help maintain a healthy balance of gut bacteria, which is essential for a strong digestive system. Not only do they improve gut health, but they also enhance immune function and promote better nutrient absorption, both critical for underweight dogs needing extra support.

For dogs struggling with weight gain due to poor digestion or past health issues, supplements like ProDog’s Boost provides a comprehensive solution. This supplement offers an all-in-one approach by delivering probiotics along with essential dog vitamins and minerals to give your dog the well-rounded nutritional support they need. Probiotics work to improve digestion, allowing your dog to absorb nutrients more effectively and making it easier for them to gain healthy weight [6].

When helping your dog on their weight gain journey, the right supplements paired with a balanced diet can make a world of difference. Probiotics, in particular, can ensure that every meal is digested efficiently, helping your dog get the most out of their food.

If you’re unsure where to begin, ProDog’s expert nutrition team is here to help. They offer FREE nutrition advice and can assist in customising a diet and supplement plan tailored to your dog’s unique needs– contact us today.

And, as always, consult your vet before adding any new supplements to your dog’s routine to ensure they meet your dog’s specific requirements.

How you feed your dog is just as important as what you feed them, especially when you’re aiming for healthy weight gain. Here are my top tips:

1. Small, frequent meals

A common mistake is offering large meals in an attempt to increase calorie intake quickly, but this can overwhelm your dog’s digestive system and lead to discomfort or even digestive issues. Instead, feeding smaller, more frequent meals throughout the day is often more effective. This method allows your dog to digest food more easily and steadily increase calorie intake without overburdening their system.

Breaking your dog’s daily food intake into several smaller meals throughout the day is key. This method helps prevent overloading the digestive system and ensures your dog is gradually taking in more calories. For underweight dogs, feeding four to six smaller meals a day can make it easier for them to absorb and process the nutrients they need to gain weight.

2. Treats and snacks

When it comes to snacks and treats, resist the temptation to load your dog up with highly processed options. Just like human junk food, the supermarket shelves are filled with products designed to attract you, but they often lack nutritional value. Instead, focus on nutrient-dense foods that offer higher levels of healthy fats, which will support sustained, healthy weight gain for your dog.

Rather than relying on processed snacks, opt for natural dog treats.  Choose high-calorie treats that add nutritional value. In between regular meals, try incorporating snacks like full-fat goat’s milk, kefir, eggs, yak bars, or even calf hooves stuffed with sheep’s fat or your dog’s fav raw dog food. Other excellent choices include beef liver and  lamb shoulder strips.

These snacks provide plenty of calories without overloading your dog’s system with fillers or artificial ingredients. When choosing dog treats, aim for minimally processed options—naturally dehydrated or raw snacks are ideal. These not only help with weight gain but can also support your dog’s digestive health. Kefir and goat’s milk, for example, are packed with probiotics, which can improve gut health and nutrient absorption, making it easier for your dog to gain healthy weight.

3. Healthy fats

Healthy fats are essential for weight gain but are often overlooked in a dog’s diet. Without enough fat, it can be difficult for your dog to reach their target weight. Fats provide a concentrated source of energy, making them an effective way to boost calorie intake without increasing meal sizes dramatically.

Incorporating fats like coconut oil, quality extra virgin olive oil, unsalted grass-fed butter, fatty fish, quality fish oils, eggs, seeds such as chia seeds, flaxseeds and hemp seeds, and avocado into your dog’s meals provides extra calories needed for healthy weight gain.

Fats are calorie-dense, so even a small amount can have a significant impact. Additionally, fats play a vital role in supporting skin and coat health, and they improve nutrient absorption, ensuring your dog not only gains weight but also thrives in overall well-being.

4. Age and Activity Level

Puppies and highly active dogs have very different caloric needs compared to older or less active dogs. Puppies, for instance, require more calories to fuel their rapid growth and development. Similarly, active dogs burn more energy and need extra calories to support their activity levels. On the other hand, senior dogs or those with lower activity may need fewer calories, but extra protein to prevent muscle wastage

Tailoring your dog’s diet to their age, breed, and activity level is key to ensuring they receive the right amount of food to promote healthy weight gain. ProDog’s raw dog food calculator is a great tool to help you determine the recommended feeding quantities. Be sure to select “gain weight” as your dietary goal. Remember, this tool provides guidelines, so it’s important to observe your dog’s progress and adjust portions accordingly to ensure optimal results.

Helping your dog gain weight isn’t something that happens overnight—it takes time, patience, and consistency. Ensure that you’re feeding a balanced diet rich in nutrients and monitoring their progress. If weight gain doesn’t happen after a few weeks, consult your vet or contact ProDog’s nutrition team.

With the right approach, you can help your underweight dog gain weight in a healthy and sustainable way, ensuring they live a longer, happier life.