Pet obesity is a growing concern and one that deserves more attention. Although it can sometimes be an awkward subject to discuss with pet owners, carrying excess weight can have a significant impact on an animal's health, mobility and quality of life.
Research consistently shows that overweight and obesity are common in companion animals. A 2026 review by researchers from the University of Sydney highlighted the widespread problem of excess weight in dogs and cats, along with its effects on animal welfare, behaviour and longevity.
Australian studies cited in the review reported that 33.5% of dogs were overweight and 7.6% were obese. For cats, 26.2% were overweight and 6.6% were obese.
Read the 2026 research review: Overweight and Obesity in Dogs and Cats.
Obesity places additional strain on the body and is associated with conditions such as osteoarthritis, cardiovascular disease, heat stress, diabetes, kidney disease and liver disease. It can also affect an animal's ability to move comfortably, play, groom themselves and engage in normal behaviours.
The good news is that sensible changes to nutrition, feeding habits and daily activity can make a meaningful difference.
At Greenpet, we believe good health starts with good nutrition. Understanding why pets gain weight and taking a holistic approach to weight management can help your companion regain vitality and maintain a healthy body condition.
Let's look at the common causes of pet obesity and how you can help your dog or cat achieve a healthier weight.
Why Do Pets Become Overweight?
Obesity develops when an animal consistently consumes more energy than they use. However, the reasons behind this imbalance aren't always straightforward. Feeding habits, genetics, age, activity levels and the home environment can all contribute.
1. Overfeeding
One of the most common contributors to pet obesity is simply feeding too much.
Many owners overestimate how much food their pets need, particularly when feeding according to packet guidelines without considering their individual activity levels and metabolism.
Treats, table scraps, dental chews and food toppers can also add considerable calories throughout the day. Even small extras can accumulate over time.
2. Lack of Exercise
Dogs and cats need opportunities to move, explore and engage in natural behaviours.
Busy lifestyles, smaller living environments and limited opportunities for outdoor activity can contribute to weight gain. Indoor cats are particularly susceptible when they have limited opportunities to climb, chase, explore and play.
3. Poor Dietary Choices
The nutritional quality of your pet's diet matters.
Highly processed foods, calorie-dense treats and diets that don't provide an appropriate balance of protein, fats and other essential nutrients can make weight management more difficult.
It's important to look beyond the quantity of food and consider its overall nutritional value.
4. Desexing and Hormonal Changes
Energy requirements can change following desexing. Some animals become more food-motivated while their daily energy requirements decrease.
If feeding portions remain unchanged, excess weight can gradually accumulate.
5. Breed and Genetic Predisposition
Certain breeds have a greater tendency to gain weight.
Labrador Retrievers, Beagles and some other breeds are particularly prone to excess weight. Genetics can influence appetite, food motivation and energy regulation.
6. Ageing
As pets get older, their activity levels and nutritional requirements can change.
Some older animals become less active and may require fewer calories. However, ageing can also involve muscle loss, making it particularly important to monitor both body fat and muscle condition.
7. Feeding Habits and Behaviour
A particularly interesting area of newer research is the relationship between animal behaviour and obesity.
A 2026 review by University of Sydney researchers highlights that obesity isn't simply a matter of feeding too much and exercising too little.
Food-seeking behaviour, boredom, environmental enrichment, interactions with owners and established feeding routines can all influence weight management.
For example, pets accustomed to receiving treats throughout the day may become frustrated when these are suddenly removed. This can make weight management challenging for both the animal and their owner.
The answer isn't simply to feed less. We also need to consider how pets interact with their environment and find ways to keep them mentally stimulated.
Read more about the behavioural aspects of pet obesity – University of Sydney, 2026.
How to Tell If Your Pet Is Overweight
You don't always need scales to recognise that your pet is carrying excess weight. Looking at their body shape and physically feeling their ribs and waist can provide useful information.
Body Condition Score (BCS)
Body Condition Scoring is a practical way to assess how much body fat your pet is carrying.
A commonly used system is a nine-point scale, with 4–5 out of 9 generally considered ideal.
An ideal body condition should include:
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Ribs that can be easily felt without excessive pressure.
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A visible waist when viewed from above.
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An abdominal tuck when viewed from the side.
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No excessive fat deposits around the abdomen or base of the tail.
If you can't easily feel your pet's ribs or distinguish their waist, they may be carrying excess weight.
Muscle Condition Score (MCS)
An important addition to modern nutritional assessment is Muscle Condition Scoring.
While BCS measures body fat, MCS assesses muscle mass and identifies muscle loss.
This is particularly important for senior pets. An older dog or cat can be overweight while simultaneously losing muscle, meaning their body weight alone doesn't tell the whole story.
Monitoring both scores provides a much clearer picture of your pet's overall body condition.
How to Help Your Pet Lose Weight Naturally
Achieving a healthy weight involves more than simply reducing food portions. The goal is to improve body composition, maintain muscle mass and provide all the nutrients your pet needs.
Here are our recommendations.
1. Review Your Pet's Diet
Nutrition is one of the most important considerations when addressing pet obesity.
We recommend moving towards a fresh, minimally processed diet that provides high-quality protein, appropriate fats and essential nutrients.
Prioritise Quality Protein
Protein is particularly important during weight management because it helps maintain lean muscle mass.
Simply reducing food portions can also reduce the amount of essential nutrients your pet receives. This is why dietary quality matters just as much as calorie intake.
Choose quality animal-based protein sources and ensure the overall diet is nutritionally balanced.
Reduce Excessive Carbohydrates
Review the carbohydrate content of your pet's current food.
Some highly processed commercial diets contain considerable amounts of starch and other carbohydrate sources. While carbohydrates aren't inherently bad, the overall composition and energy density of the diet should be considered.
We prefer fresh food options that provide quality animal protein and a natural balance of nutrients.
Consider Wet Food and Fresh Food Options
Wet and fresh foods can be useful when managing calorie intake because their higher moisture content generally means fewer calories per gram than dry food.
For dogs and cats, consider transitioning towards a suitable fresh or wet food diet.
You can explore our natural feeding guides:
Remember that home-prepared diets need to be properly balanced. Simply feeding meat and vegetables doesn't provide all the nutrients dogs and cats require.
If you're changing your pet's diet, introduce new foods gradually to minimise digestive upset.
2. Measure Food Portions Carefully
Even a high-quality diet can contribute to weight gain when fed in excessive quantities.
Rather than relying solely on feeding recommendations printed on packaging, consider your pet's individual requirements.
Factors to consider include:
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Current body weight and ideal body condition.
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Age and life stage.
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Breed and genetic predisposition.
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Desexing status.
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Daily activity levels.
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The calorie content of their food.
Weighing food portions using kitchen scales is generally more accurate than measuring cups.
Avoid making drastic reductions in food intake.
Weight loss should be gradual, allowing your pet to maintain muscle mass and receive adequate nutrition. This is particularly important for cats, as rapid weight loss and inadequate food intake can lead to serious metabolic complications, including hepatic lipidosis (fatty liver).
A personalised feeding plan is preferable to applying a universal percentage of body weight to every animal.
3. Keep Treats Under Control
Treats are often overlooked when calculating daily food intake.
A few biscuits, table scraps or training rewards can quickly add up, particularly in smaller dogs and cats.
As a general nutritional guideline, treats and other extras should make up no more than 10% of daily calorie intake. The remaining 90% should come from a complete and balanced diet.
Some healthier treat alternatives include:
You can also use small portions of your pet's regular food as rewards.
For cats, interactive feeding toys can make mealtimes more interesting while encouraging natural hunting and foraging behaviours.
4. Consider Nutritional Supplements
When adjusting your pet's diet, it's important to maintain adequate nutrient intake.
A suitable multivitamin and mineral supplement may be worth considering, particularly when portions are being reduced or dietary variety is limited.
We recommend exploring:
There are also several nutrients and natural compounds that have attracted interest in weight and metabolic health research.
L-Carnitine
L-Carnitine is a naturally occurring compound involved in transporting long-chain fatty acids into the mitochondria, where they're used in energy production.
It has been investigated for its potential role in supporting fat metabolism and maintaining lean body mass.
A 2026 pilot study investigated L-Carnitine supplementation in overweight dogs. The researchers observed changes in body condition scores and selected metabolic markers over 30 days, although the dogs didn't experience measurable weight loss during the study.
The research is preliminary and further controlled studies are needed.
Read the 2026 L-Carnitine research.
Explore Greenpet L-Carnitine Powder.
Omega-3 Fatty Acids
Omega-3 fatty acids are important essential fats that contribute to normal cellular function and overall health.
They are particularly relevant when considering the nutritional needs of overweight animals, as maintaining an appropriate balance of essential fatty acids is important when adjusting dietary intake.
Probiotics and Gut Health
Gut health is another interesting area of research.
A 2024 study published in Microbiology Spectrum investigated probiotic supplementation in obese dogs and its relationship with gut microbiota, energy metabolism and weight changes.
Another 2024 study investigated specific strains of Lactiplantibacillus plantarum and Bifidobacterium breve in overweight dogs.
These findings are interesting, but the results relate to the specific probiotic strains and formulations studied. They shouldn't be assumed to apply to every probiotic supplement.
Read the 2024 probiotic research – Microbiology Spectrum.
Wakame
Wakame is a brown seaweed containing a naturally occurring carotenoid called fucoxanthin.
Fucoxanthin has attracted research interest for its potential involvement in lipid metabolism and energy regulation. However, most of this research has been conducted outside companion animals, so its practical effects on canine and feline weight management remain uncertain.
We wouldn't rely on Wakame as a weight-loss supplement, but it is an interesting ingredient from a nutritional research perspective.
5. Increase Daily Activity and Exercise
Exercise is important for maintaining muscle mass, supporting mobility and encouraging healthy metabolic function.
However, the type and amount of activity should suit your pet's age, fitness and current body condition.
For Dogs
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Establish a regular walking routine.
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Gradually increase walking duration as fitness improves.
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Encourage sniffing and exploring on walks.
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Introduce games such as fetch where appropriate.
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Use food puzzles and enrichment activities.
For dogs carrying considerable excess weight, start with shorter, manageable walks rather than expecting them to complete long distances straight away.
For Cats
Cats need opportunities to express their natural hunting and climbing behaviours.
Try introducing:
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Interactive feather toys.
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Short play sessions throughout the day.
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Cat trees and climbing shelves.
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Food puzzles and foraging toys.
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Small portions of food hidden around the home.
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Harness walks for cats that enjoy exploring outdoors.
Several short play sessions can be more manageable than trying to encourage one long period of activity.
6. Make Mealtimes More Interesting
One of the most overlooked aspects of weight management is the way pets receive their food.
Instead of simply placing food in a bowl, consider introducing activities that encourage natural foraging behaviours.
Puzzle feeders, slow feeders and food-dispensing toys can help make mealtimes more engaging.
For multi-pet households, feed animals separately to prevent one pet from eating another's food.
This is particularly important when one animal requires a different feeding allowance or diet.
7. Monitor Weight and Body Condition
Consistency is key when managing pet obesity.
Keep a record of your pet's weight and body condition so you can identify changes over time.
We recommend:
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Weighing your pet regularly.
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Recording their Body Condition Score.
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Monitoring muscle condition, particularly in senior pets.
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Reviewing food portions as their weight changes.
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Adjusting activity levels as fitness improves.
Don't focus solely on the number on the scales. Changes in muscle mass and body fat are equally important.
Maintaining a Healthy Weight Long Term
Once your pet reaches their ideal body condition, the next challenge is maintaining it.
Many animals gradually regain weight when previous feeding habits return.
The key is to establish sustainable routines that become part of everyday life.
Continue measuring food portions, limit excessive treats and maintain regular exercise and enrichment activities.
It's also worth reassessing your pet's nutritional requirements as they age, become less active or experience changes in their health.
Remember, a healthy weight isn't about having the smallest possible pet. It's about maintaining an appropriate balance of body fat, muscle mass, nutrition and activity.
Final Thoughts
Pet obesity is more than a cosmetic issue. Carrying excess weight can affect an animal's mobility, comfort, behaviour and overall quality of life.
The most effective approach considers the whole animal rather than focusing on food portions alone.
Good nutrition, appropriate feeding habits, regular movement and mental enrichment all play an important role.
At Greenpet, we believe that providing pets with quality nutrition and supporting their natural health is fundamental to their long-term wellbeing.
Small, consistent changes can make a big difference. Start by reviewing what your pet eats, how much activity they receive and whether their current routine is supporting a healthy body condition.
Your pet will thank you for it!
Research references: