Why Is My Cat Losing Weight? Top 5 Causes Explained

Cats are known to be precise eaters, typically regulating their food intake to maintain a healthy weight. Unlike many dogs, they rarely overeat and are content to nibble small meals throughout the day. However, if you notice your cat losing weight without an obvious reason, it is a sign that something could be wrong and requires attention.

Unexplained weight loss in cats can be concerning and may indicate underlying health or environmental issues. It's important to observe your cat closely and explore the potential causes to ensure timely care and intervention.

Here, we outline the five main reasons why cats lose weight, along with practical advice on how to support your feline friend through each situation.

1. Unpalatable Food and Feeding Issues

If your cat is turning their nose up at their meals, this could lead to insufficient calorie intake and subsequent weight loss. Cats are particular about taste and texture, and disliked food can make them eat less or seek alternative food sources, including hunting.

Ensure your cat’s feeding area is clean and inviting. Dirty or old bowls coated with dried food residues can put even the most hungry cat off eating. Experiment with different high-quality, palatable foods to find one your cat enjoys, especially if they are showing signs of ageing or dental issues.

2. Worms and Other Intestinal Parasites

Intestinal parasites such as worms can cause significant weight loss in cats by impairing nutrient absorption and causing digestive upset. Cats that roam outdoors or hunt prey are at a higher risk and may require more frequent worming treatments.

Keep your cat’s worming schedule up to date with products recommended by your vet. Regular faecal examinations can help detect parasite infestations early and prevent complications.

3. Stress and Environmental Changes

Cats are sensitive animals easily affected by stress from environmental changes. Situations like moving house, new pets or people in the home, or loud noises can impact their appetite and behaviour.

Signs of stress besides weight loss include hiding, destructive behaviour, inappropriate toileting, and spending excessive time away from home. Identifying and reducing stressors by providing a calm, predictable environment and safe spaces can improve your cat’s wellbeing and appetite.

4. Age-Related Changes Affecting Appetite

As cats grow older, natural ageing processes can lead to weight loss and changes in eating behaviour. Dental problems may make chewing difficult, necessitating softer foods. Additionally, diminished senses, particularly smell and taste, can reduce food appeal.

Mature cats (over eight years old) often benefit from specialised diets formulated to support aging organs and maintain a healthy weight. Adding aromatic wet foods or warming meals slightly can stimulate appetite.

5. Underlying Health Problems

Several medical conditions can cause weight loss despite normal or increased food intake. Common illnesses include:

• Hyperthyroidism: Overactive thyroid increases metabolism causing weight loss, often with increased hunger and thirst.
• Diabetes Mellitus: Insulin dysfunction leads to rapid weight loss, increased urination, and thirst.
• Inflammatory Bowel Disease: Causes poor nutrient absorption and digestive symptoms.
• Kidney Disease: Common in older cats, leading to loss of appetite and weight.
• Cancer: Can cause severe weight loss alongside lethargy and other symptoms.

If other causes have been ruled out, consult your vet for a comprehensive examination. Blood tests, urine analysis, and imaging may be necessary to diagnose and treat the underlying disease effectively.

When Should You See a Vet?

Prompt veterinary attention is crucial if your cat is losing weight without explanation. Early diagnosis and treatment improve prognosis significantly. Observe your cat’s overall behaviour, eating patterns, and any additional symptoms to provide useful information to your vet.

Maintaining regular health checks, parasite control, a stress-free environment, and appropriate nutrition will help keep your cat healthy and happy for years to come.