The easy and healthy weight loss in cats

Weight loss, whether for overweight cats, dogs or humans, is said to improve the health of the subject. That is certainly true, but in order to become a reality, weight loss must be carried out the right way. Even if it’s “just a cat!”

Woman overfeeding a pet cat
In this article you will learn how to help your cat lose weight healthily and realistically. You will learn how to calculate the amount of food your cat really needs, and you will also find some tips to implement when you put your cat on a diet.

We have mentioned the risks of a cat being obese, but that’s one thing. Putting a cat on a crash diet can lead to certain health disorders, such as hepatic lipidosis (very common in starving cats) and heart conditions. So a crash diet isn’t the solution, but a diet does need to provide some readily apparent results or you might lose interest. The best approach is a diet that aims for a weight loss of about 2-4% of your cat’s total body mass.

To diet or not? The most popular approaches to cat weight loss

We–the authors of this website–follow a very efficient weight loss method for ourselves. We don’t go for special diets. We simply eat healthy, balanced food every day. We do not overeat, and we make sure to get enough exercises. We take the same approach with our pets and our clients’ pets.

The veterinary world currently uses two different methods when it comes to putting a cat on a diet.

  • Weight loss method #1: Feed your cat the amount of food appropriate to his desired weight.
    • Good – very few calculations are necessary; you don’t need to adjust the food amount as your cat loses weight.
    • Bad – it’s tricky to tell the “ideal weight”; an excessively overweight cat can lose weight at an unhealthy rate.
  • Weight loss method #2: Feed your cat 60%-90% of the food required according to maintain his current weight (his unhealthy weight).
    • Good – provides gradual (and healthy) weight loss; does not require you to evaluate your cat’s “desired” weight.
    • Bad – may be harder if you don’t like math.

In general, we suggest the first approach when a cat is no more than 20% over his normal weight, and approach #2 when a cat is obese, or more than 20% over what his normal weight should be. With any diet you should aim for 2-4 % of body weight loss per week at maximum.

Cat weight loss for moderately overweight pets (less than 20% above ideal weight)

Cat food measuring cup
Practical tip: Measure your cat’s daily food requirements in a cup and serve in several meals throughout the day. Do not offer any extra treats.

With method #1 the trickiest part is to determine your cat’s ideal weight. We already talked about assessing if your cat is overweight, and one of the methods was comparing your cat to other cats of the same age, breed and sex. But it’s hard. You can know that the average cat weighs between 4 and 5 kilos, and some breeds, such as Maine Coon, Persian, Siamese and Ragdolls, are larger, but that still leaves a lot of room for interpretation. You can try this tool by PET-MD to assess your cat’s body condition.

After you get through the tricky part of determining your cat’s ideal weight, check the label on the cat food you use and look for “Recommended Feeding Guidelines.” You will find a table with a range of daily food requirements depending on your cat’s weight. Good! Now feed your cat the amount of food he  should eat if he were at his ideal weight. This is where it ends. After several weeks or months, your cat should arrive at his ideal weight, and–as long as you don’t increase the amount of food given–should stay at it. N.B.: This method is not recommended if your cat is severely obese.

Weight loss for obese cats (more than 20% of ideal weight)

With method #2 you can leave out all the guesswork, as you do not need to know your cat’s “ideal” weight. All you need to know is how many calories your cat needs daily to sustain himself. That calls for a calculator.

  1. Find the recommended feeding guidelines on the cat food package. It’s a table with a range of daily food requirements depending on your cat’s weight.
  2. Check the amount of food recommended for your cat’s CURRENT weight. If there’s a range (from … to …), choose the smaller amount.
  3. Multiply this number by 0.6. You can use 0.9, or something in between, if your cat is severely obese. The latter will prevent too-rapid weight loss.
    NOTE: If there are no recommended feeding guidelines, use this: an overweight cat needs 130 × (weight in kilos)0.4 or 130 × (weight in lbs. × 0.45)0.4 f. Multiply this number by 0.6 or 0.9 to get the amount of calories your cat needs for healthy weight loss.
  4. Weigh your cat again in two weeks. Most likely, his or her weight will be reduced. Recheck the label and lower the amount of food again.

Cat’s diet calculation example #1:

Adult cat weighs 7 kg. It is not known what his ideal weight should be, but physical body shape evaluation reveals that the cat is obese. Owner uses cat food which states that a 7-kg cat should consume 80-90 grams of cat food daily to maintain the weight.

Amount of food necessary to lose weight = 80 × 0.6 = 48 [grams/day]

Owner decides to feed the cat 48 grams per day and weighs the cat after two weeks.

Cat’s diet calculation example #2:

The same cat as above, obese. Owner uses cat food that states that 100 grams of the food contains 364 kcal.

Energy requirement for maintenance = 130 × 70.4 = 283 [kcal/day]

Necessary daily caloric intake for weight loss = 283 × 0.6 = 169 [kcal/day]

Amount of food necessary for weight loss = 100 × 169 ÷ 364 (from label) =  46.5 [grams/day]

As you can see, both calculation examples arrived at approximately the same result. That’s good, because we used the same cat food for both calculations.

The calculation in example #2 should be done only if there are no feeding guidelines. That is most likely to happen when you prepare the cat food yourself, which will also require a calculation of calories of the ingredients used. We won’t cover this here, however.

Once you have determined the amount of food your cat needs, feed your cat accordingly for one or two weeks. Weigh him or her again, do the recalculations and continue the pattern until your cat reaches an ideal body condition (as described in our previous article).

Have you decided to put your cat on a diet? That’s good, because in our next article you will learn several additional tips to help your cat lose weight efficiently, healthily and pleasurably as the final part of our series to stop and prevent obesity in cats.