Is your cat at a healthy weight? Studies show that approximately 40-50% of domestic cats are overweight or obese, yet many owners don’t realize there’s a problem. Making matters worse, chubby cats look adorable, so we don’t always see it as a health concern. This guide teaches you how to properly assess your cat’s body condition and why it matters.
Why Weight Matters
Obesity isn’t just a cosmetic issue—it directly affects your cat’s health and lifespan.
| Health Risk | Details |
|---|---|
| Diabetes | Obese cats are over 4 times more likely to develop diabetes than cats at healthy weight |
| Osteoarthritis | Extra weight accelerates joint cartilage wear, causing chronic pain |
| Cardiovascular strain | The heart has to work harder, increasing heart disease risk |
| Urinary problems | Obesity is associated with urinary tract disease |
| Anesthesia risk | Higher complication rates during surgery |
| Shortened lifespan | Research suggests obesity may shorten a cat’s life by 2-3 years |
The good news is that weight can be managed. The first step is learning to properly assess your cat’s current body condition.
Body Condition Score (BCS): More Important Than the Number on the Scale
Many people only look at the weight on the scale, but that’s not accurate enough. A 5 kg Maine Coon might be underweight, while a 5 kg mixed breed could already be overweight.
Veterinarians use “Body Condition Score” (BCS) to evaluate a cat’s body fat level. The most common system uses a 9-point scale, developed by the World Small Animal Veterinary Association (WSAVA).
How to Assess
Evaluating BCS requires both looking and feeling, checking three areas:
1. Ribs
- Gently run your palms over your cat’s rib area (don’t press hard)
- Ideal: You can easily feel the ribs, but can’t see obvious rib outlines
- Overweight: You need to press firmly to feel ribs, or can’t feel them at all
2. Waist
- View your cat from directly above
- Ideal: There’s a visible waist curve behind the ribs (like the top of an hourglass)
- Overweight: No visible waist; body appears oval or rectangular
3. Abdomen
- View from the side
- Ideal: The belly line tucks up slightly from chest to rear
- Overweight: Belly sags, or runs parallel to the ground
BCS Reference Chart
| Score | Condition | Characteristics |
|---|---|---|
| 1-3 | Underweight | Ribs, spine, and pelvis clearly visible; minimal fat covering |
| 4 | Lean | Ribs easily felt and may be slightly visible; obvious waist |
| 5 | Ideal | Ribs easily felt with slight fat covering. Waist visible from above; abdomen tucks up |
| 6 | Slightly overweight | Ribs require slight pressure to feel; waist less distinct |
| 7 | Overweight | Ribs difficult to feel; no waist; abdomen becoming rounded |
| 8-9 | Obese | Cannot feel ribs; obvious belly sag; body appears round from above |
Want a visual reference? See the official WSAVA Body Condition Score chart (PDF).
The goal is BCS 5. If your cat is at 6-7, it’s time to pay attention; at 8-9, consult your veterinarian soon.
Muscle Matters Too
It’s worth noting that body condition score only evaluates fat, not muscle. Some cats can be both “overweight” and “muscle-wasted”—looking round overall while the spine and shoulder blades become prominent.
This is particularly common in cats over 10 years old. If you notice your cat’s back muscles have noticeably decreased, even if weight hasn’t dropped, consult your vet to rule out underlying health issues.
Why Cats Gain Weight Easily
Understanding the causes helps with prevention.
Metabolic Changes After Neutering
Neutering reduces a cat’s basal metabolic rate by about 20-30% while potentially increasing appetite. This means if you maintain the same feeding amount, weight gain is likely.
Recommendation: Discuss adjusting food portions with your vet after neutering—typically a 20-30% reduction is needed.
Free-Feeding
Leaving dry food out all day for cats to eat whenever they want is a major cause of obesity. In the wild, cats are “small, frequent meal” hunters, but faced with an endless food supply, many cats will overeat.
Recommendation: Switch to scheduled, portioned meals—2-3 times per day.
Indoor Lifestyle
Indoor cats are far less active than outdoor cats, naturally burning fewer calories. Add in lack of environmental stimulation, and some cats eat out of boredom.
Recommendation: Increase interactive play time; provide vertical spaces and puzzle feeders.
Owner Underestimation
This may be the biggest issue. Research shows that owners typically rate their cat’s body condition 1-2 points lower (better) than veterinarians do. When “slightly chubby” is seen as “normal,” the problem gets overlooked.
How to Help Your Cat Maintain a Healthy Weight
Dietary Adjustments
- Scheduled portions: 2-3 meals per day, not free-feeding
- Wet food preferred: Canned food has high water content (70-80%), typically higher protein and lower carbohydrates than dry food
- Calculate calories: Discuss your cat’s daily caloric needs with your vet
- Limit treats: Treats should be no more than 10% of daily intake
Increase Activity
- At least 15-20 minutes of interactive play daily (wand toys, laser pointers, etc.)
- Use food puzzles to make your cat “hunt” for meals
- Provide cat trees and vertical spaces
- In multi-cat homes, ensure adequate resources to prevent stress eating
Weight Loss Rate
If weight loss is needed, it must be gradual.
Important Warning
Cats must never lose weight rapidly. If a cat suddenly reduces food intake significantly, the body begins breaking down fat, which can lead to “hepatic lipidosis” (fatty liver disease)—a potentially fatal condition.
A safe weight loss rate is 0.5-2% of body weight per week. A cat that needs to lose 1 kg may take 3-6 months to reach the goal safely.
Weight loss programs are best conducted under veterinary guidance, especially for obese cats at BCS 8-9.
When to See the Vet
Consider scheduling a veterinary consultation if:
- BCS reaches 7 or higher
- Weight has increased or decreased significantly in a short time
- Weight continues to rise despite dietary control attempts
- You’re unsure what your cat’s ideal weight should be
- You want to create a safe weight loss plan
Your vet can rule out underlying conditions causing weight issues (such as thyroid problems) and provide individualized dietary recommendations.
Tracking Weight Changes
Long-term weight trends reflect health status better than single measurements. We recommend weighing every 2-4 weeks and recording the data to observe changes.
Weighing Tip
Use a baby scale, or hold your cat while standing on a scale (then subtract your own weight). Measure at the same time and under the same conditions each time for more accurate data.
Key Takeaways
Your cat’s body condition score reflects health status better than weight alone. Learn to look and feel—regularly check the ribs, waist, and abdomen to catch weight issues early. The goal is maintaining around BCS 5. If your cat is already overweight, don’t worry—with proper dietary adjustments and increased activity, most cats can gradually return to a healthy weight.
References
- WSAVA Global Nutrition Committee. (2020). Body Condition Score - Cat. WSAVA
- Cornell University College of Veterinary Medicine. (2024). Obesity. Cornell Feline Health Center
- Saavedra, C., et al. (2024). Overweight and obesity in domestic cats: epidemiological risk factors and associated pathologies. Journal of Feline Medicine and Surgery. PMC
- Teng, K.T., et al. (2018). Associations between neutering and obesity in domestic cats. Journal of Feline Medicine and Surgery, 20(12), 1054-1064.
- German, A.J. (2006). The growing problem of obesity in dogs and cats. The Journal of Nutrition, 136(7), 1940S-1946S. PubMed
