Why Is My Cat Losing Weight But Still Eating?

Why Is My Cat Losing Weight But Still Eating

Having a pet and then seeing them get old and lose weight surely hurts, but it is important to know the reason behind why your cat is losing weight despite eating. When your cat is still eating, unintentional weight loss can be a dangerous sign of a serious underlying medical condition. So, let us discuss it. Read below to find out. 

Why Is My Cat Losing Weight But Still Eating?

If your cat is losing weight while still eating food properly, then it is most probably due to one of the many reasons listed below:

1: Hyperthyroidism

Hyperthyroidism is where thyroid hormone is produced more than the required amounts. It is quite common in older cats and starts as a benign tumor in the thyroid gland. In hyperthyroidism, cats eat properly or even eat more food. Along with losing weight, cats also face increased thirst, increased urination, vomiting, and diarrhea. 

2: Cancer

Cancer is common among older cats and can occur in part of the body just like humans. Cancer can cause reduced appetite, pain, lethargy, and dizziness in cats. Cancer cachexia also happens in cats where their body starts to break down their own muscles and fats which impairs their digestion ability and causes weight loss. 

3: Kidney Disease 

Kidney disease is common among older cats where they feel increased thirst, more urination, and ultimately a reduction in their body weight. Drinking more water and expelling more urine causes a lot of fluids and nutrients to pass out from the body. In kidney disease, the functioning of the kidney is reduced which causes toxins to build up in the body affecting the metabolism and appetite of your cat. 

4: Intestinal Parasites

Stomach and intestinal parasites like tapeworms and tubeworms are really common causes of weight loss in cats and can be transferred from cats to rodents when cats eat them. These worms affect nutrient absorption, and cause vomiting, and diarrhea that results in weight loss. These worms are present in their stools, so it is important to look for the worms in the stool of your cat so that it can be treated. These intestinal parasites can cause vomiting, diarrhea, bloating, and difficulty breathing. 

5: Intestinal Problems

Gastrointestinal problems like inflammatory bowel disease or pancreatitis can cause weight loss in cats even if they are eating proper food. It can affect nutrient absorption, and cause vomiting, and diarrhea that results in weight loss. Some other intestinal problems that cause weight loss in cats include intestinal infections or food allergies that can cause inflammation and GI irritation. 

6: Respiratory Infection 

Respiratory infections like pneumonia and other respiratory infections can also cause weight loss even if your cat is eating proper food. 

7: Diabetes

Diabetes is another reason for weight loss in cats, especially feline diabetes, which is due to a lack of insulin production or the body is unable to respond to it. In addition to weight loss, it also causes increased thirst, increased urination, urinary tract infections, lethargy, and smelly breath 

What To Do If Your Cat Is Losing Weight?

Your cat can lose weight due to any of the reasons. It is important to take your cat to the vet as soon as you notice a drop in their weight if they are still eating. The vet will do a complete examination and determine the cause of weight loss will start the treatment and give you suggestions regarding their diet and how to take care of your cat. 


If your cat is losing weight but still eating, then the possible reasons for losing weight are hyperthyroidism, cancer, kidney disease, intestinal parasites, intestinal parasites, respiratory infection, or diabetes. All these health problems either affect the appetite, and metabolism causing vomiting and diarrhea, or interfere with the absorption of nutrients. 

About the author