At a time when half the pet population is overweight or obese, it’s easy for pet parents who notice their furry friends trimming down to give them two paws up. However, on the other end of the scale, if weight loss seems effortless or is unintended, there could be underlying illness to blame.
Take note of your pet’s appetite, as it may give you some clues as to why your pet is losing weight. For instance, cats with hyperthyroidism typically lose weight despite an increased appetite, whereas pets with other illnesses won’t feel like eating. Obese cats are particularly prone to a life-threatening condition called hepatic lipidosis (or fatty liver disease), so warning flags should go up if you notice your cat shunning his food.
Other conditions that can cause rapid weight loss include:
Dental disease/Oral pain
Bowel disease (malabsorption/maldigestion)
Protein-losing enteropathy or nephropathy
Your vet uses both your pet’s weight and “body condition score” to assess her health, so even if you can’t get your pet onto a scale, you can still watch for changes in her shape — like muscle loss or prominent ribs or spine — to monitor weight loss or gain. If you are seeing changes to your pet’s weight or condition without changes to diet or exercise, it’s time to schedule a checkup.