Why Cats Eating Tuna May Gain Weight

Most indoor cats aren't very active and don't require a lot of calories — meaning weight gain can easily creep up. According to recommendations set forth by the World Small Animal Veterinary Association, a cat that weighs 5 kg should consume 290 calories per day.

When human foods are converted to cat calories, it is easy to see that foods intended for humans have far too many calories for our feline companions. A small amount of canned tuna in water can contain almost 100 calories, which is more than a third of the recommended daily caloric intake for many cats.

In turn, eating too much tuna can cause your cat to gain significant weight, especially when fed in addition to their normal cat food. Just like in humans, obesity in cats contributes to health concerns such as diabetes, bladder problems, arthritis, and cancer, according to the PDSA.

Monitoring food consumption is very important when managing your cat's health. As more manufacturers include calorie content information on pet food labels, it is easier to judge how many calories you are feeding your pet per day. This is great news for cat parents, as more information can lead to more informed decisions about food, and ultimately better health for their cat.

Not All Cats Can Stomach Tuna

Cats can also be allergic to fish. Fish is one of the most common causes of food allergies and food intolerance in cats. Common signs of an allergic reaction include itching, hair loss as well as red, inflamed skin. Cats with food allergies may also vomit and experience diarrhoea, gas and a loss of appetite if they encounter an ingredient they're sensitive to. If you notice any of these symptoms, call your veterinarian right away to determine the causes and create a treatment plan.

Tuna Is High in Mercury

Tuna is high in mercury, a toxic metal. Frequent consumption of tuna may also lead to mercury poisoning, explains Cailin Heinze, a veterinary nutritionist at the Cummings School of Veterinary Medicine at Tufts University. Symptoms of mercury poisoning include dizziness and loss of coordination and balance. Pet parents should keep albacore tuna, in particular, away from cats because it "is from a larger species of tuna with mercury levels almost three times higher (than chunk-light)", says Heinze.

So, can cats eat tuna? Tuna is not nutritionally balanced and should not be fed as a large part of your cat's meal plan. Even giving canned tuna as a treat can lead to health issues, especially if it is given in large amounts or frequently. To ensure your feline friend is getting the balanced nutrition they need without extra calories or toxic metals, choose a healthy cat food that uses tuna in a way that still meets their nutritional needs and satisfies their taste buds.