Pets can’t tell us when they are in pain or feel unwell, but their behavior can give us important clues about their internal wellbeing. Your pet’s appetite and thirst are two major health indicators that can help you determine when to schedule an appointment with our Bayview Animal Hospital team. Learn nine reasons why your pet’s eating or drinking habits have changed.

#1: Thyroid disease in pets

The thyroid gland regulates the body’s metabolism. When this gland is damaged because of immune-mediated destruction, benign or neoplastic growths (i.e., cancer), dietary imbalance, or another disease process, pets can experience extreme changes in their eating and drinking habits.

Weight loss despite a ravenous appetite is a hallmark hyperthyroidism sign in cats. Affected cats also experience increased thirst and urination, and because they feel too ill to groom, their fur becomes unkempt or matted.

#2: Urinary tract problems in pets

Responsible for waste filtration and elimination, your pet’s urinary tract encompasses their kidneys, ureters, urinary bladder, and urethra. Any urinary tract abnormality can cause a pet’s thirst to increase as the body filters out increased volumes of water, and their appetite may decrease as they experience pain or nausea from increased bloodstream toxins. However, some pets’ thirst decreases when they have a urinary tract disorder.

In addition to changes in their food or water intake, pets with urinary tract conditions may strain to urinate, urinate frequently, vocalize during urination, have discolored or bloody urine, or demonstrate inappropriate elimination (i.e., urinary accidents).

#3: Diabetes in pets

Excessive thirst and urination are dogs’ and cats’ classic diabetes signs. Two diabetes types affect pets. Diabetes mellitus is caused by inadequate insulin production in the pancreas, while diabetes insipidus occurs when the body doesn’t produce enough antidiuretic hormone (ADH), or their kidneys fail to respond appropriately to ADH. In both conditions, pets urinate more and must increase their water intake to avoid dehydration. If you suspect your pet has diabetes, they should have a veterinary examination. If your veterinarian diagnoses your four-legged friend with diabetes, they will prescribe effective treatment. To help prevent your diabetic pet from having a potentially life-threatening emergency, such as hyperglycemia, hypoglycemia, and diabetic ketoacidosis, you must monitor them closely at home.

#4: Cushing’s disease in pets

Cushing’s disease (i.e., hyperadrenocorticism) occurs most often in dogs and is considered rare in cats. Pets with Cushing’s disease experience abnormally high cortisol levels caused by long-term steroid administration, adrenal gland abnormalities, or an adrenal or pituitary gland tumor. Excessive cortisol disrupts healthy metabolism, which results in an affected pet experiencing increased appetite, thirst, and urination.

Cushing’s disease often requires lifelong management and monitoring. If your dog has Cushing’s disease, they may exhibit signs such as skin and coat changes, a pot-bellied appearance, and muscle atrophy (i.e., loss or wasting).

#5: Cancer in pets

Depending on a tumor’s type and location, cancer can increase or decrease your pet’s appetite. Cancer robs pets of nutrition, using carbohydrates, fat, and protein to fuel a tumor’s rapid growth and spread. As a result, some pets may experience a voracious appetite despite losing weight and muscle (i.e., cancer cachexia). Some cancers cause pets pain or nausea, which results in a decreased appetite or finicky behavior. Pets with cancer may also experience increased thirst.

#6: Medication side effects in pets

Certain medications cause appetite and thirst-altering side effects. Although your veterinarian will advise you about your furry pal’s prescription, keep in mind that each pet can have a unique reaction to a medication. Talk to your veterinarian if your pet’s unusual thirst or appetite occurred after starting a new medication. The most common appetite- and thirst-altering medications include:

  • Steroids
  • Antibiotics
  • Pain medications
  • Diuretics
  • Chemotherapy 
  • Antiseizure medications

#7: Stress and anxiety in pets

Stress triggers numerous harmful changes throughout the body, including increased cortisol and adrenaline release. These chemical changes cause high blood pressure and decreased immunity, which in turn raises a pet’s risk for heart disease, and gastrointestinal (GI) and respiratory problems. Stressed pets generally feel unwell and may experience nausea and appetite loss, while others may compulsively eat or drink in an attempt to relieve boredom or soothe their rattled nerves. Additional stress and anxiety signs include destructive, reactive (i.e., hypervigilant), or attention-seeking behaviors and digestive disruptions (e.g., vomiting or diarrhea).

#8: Diet change in pets

Diet changes can be upsetting for pets, especially if a dog or cat is finicky about their food. Diet change can lead to food refusal and appetite loss. Alternatively, if they enjoy their new food, a pets’ appetite may increase. A new diet can also cause a pet’s thirst to change. High-sodium or dry diets can promote increased thirst, while reduced-sodium, moist, or wet diets can lead to decreased thirst. 

#9: Life stage changes in pets

Your pet’s appetite and thirst may vary depending on their life stage. While growing puppies and kittens, and pregnant or lactating females require increased nutrients for proper development, spayed, neutered, and senior pets generally have a lower calorie requirement and may be content with smaller food portions. Your Bayview Animal Hospital veterinarian can advise you on the food and amount you should feed your pet at each life stage.

Although your pet may occasionally skip a meal or drink more water during hot weather, this is normal. However, persistent changes in your pet’s food or water intake warrant a visit to Bayview Animal Hospital. If your pet’s thirst or appetite has inexplicably changed, schedule an appointment or request one online.