How to tell if your pet is overweight, and what to do about it

The First Step:

Determine if your pet is ideal weight or overweight. If you need some help, read my article on determining body condition score and the groundbreaking Labrador longevity study. 

Your pet’s vet can also help with body condition scoring, tracking weight values, determining if your pet is overweight, and designing a weight loss plan.

The Second Step:

The next thing we look at is both sides of the energy equation : energy in versus energy out.

A pet becomes overweight when there is more energy in than out, but unfortunately it is nearly impossible for significant weight loss to occur with only increasing exercise (increasing energy spent).

For a pet to lose weight we must feed it less energy.

What Should We Feed?

Let me show you how to sidestep a common mistake that many pet owners make when tackling a weight problem.

Many will start this weight loss process by feeding the same food, just less of it. Many foods are quite calorie-dense, meaning that there are many calories in a small amount and a very drastic reduction in the portion size is necessary to get significant weight loss.

This can be problematic for a couple of reasons:

1. Your pet will rebel! Sometimes loudly, over and over again…sometimes at 3 am!
2. Your pet may not be getting adequate protein and nutrients in this small volume of food to maintain muscle mass and health during weight loss.Most owners never get to the point of restricting the food enough for weight loss anyway, and give up early on in the whole process.

The better choice is to start with a diet especially designed to give a pet the optimal nutrition it needs while losing weight.

Veterinary Weight Loss Diets

1. Low-Calorie in a Larger Volume 

• Lower fat, increased fiber/water
• Pets feel fuller, reducing begging
• You can give your pet a satisfying portion without overfeeding

2. Nutrient Fortified- When we feed fewer calories, we only want to drop the calories, not the vital nutrients

• High nutrient-to-calorie ratio: Provides essential proteins, vitamins, and minerals even when calories are reduced.
• Prevents muscle loss: Maintains muscle mass during weight loss, reducing the risk of weight regain.

But Kitty Bubs loves his cookies…

Treats can be 10% of the day’s calories, but we need to look closely at the calorie content of the treat. Some, like cheese, are very calorie dense. 

One trick for cats on a diet is to tempt them to eat vegetables that are coated in Purina Fortiflora Probiotic. They seem to really like it! 

How do I even know the goal weight of my pet? 

One method is to look at what your pet weighed at 12-15 months of age, and start with that weight as a goal. 

Hill’s Pet Food has a great weight estimator chart that gives an estimate of ideal weight based on the percentage of body fat your pet has. This can be estimated from Body Condition Score (BCS).

Hill’s Ideal Body Weight Indicator

Check out the Hill’s Ideal Body Weight Estimator for Cats.

How much do we feed? 

There is no one size fits all solution. And the starting amount is just that- a starting point. Adjustments are made depending on the response. 

Methods of determining initial amount of food:

1. Calculate current calories fed and feed 20% less

• Weigh the current amount of food that is being fed daily.
• Weight is much more accurate than a measuring cup, especially for making small adjustments.
• Calculate calories in the daily amount of food based on Kcal/ Kg 
• Decrease by 20%

Always use a scale! It is much more accurate, especially for small adjustments.

2. Use standard energy requirement calculations based on the estimated ideal weight

• Resting energy requirement (RER): the commonly used formula RER= 30 × (body weight in kg) + 70 = RER in kcal/day
• should not be used for patients weighing less than 2 kg or more than 45 kg.
• For dogs, we generally start at 80% of RER for a diet (0.8 X RER)
• cats often require more aggressive restriction, like 60-70 % of RER.

TIPS:

We don’t want to decrease a pet’s weight too rapidly. Monitoring weight loss is critical. 

Weight the daily amount of food to be given, put it in a container and have the whole family feed only from that.

Change foods gradually, over a few days, as special weight loss diets have more fiber and a fast change could cause an upset stomach.

What else can we do? 

Increase exercise: with a bit of caution and moderation to start, as overweight pets are more prone to injury. Talk to your vet, if your pet has a history of injuries, to develop a safe exercise plan. 

Try 5 minutes of intense play, three times a day with cats and food puzzles for feeding to increase activity. 

When should we check? 

Ideally, reweigh your pet every 2-4 weeks with an accurate scale. 

It may be best to visit your vet clinic to do this, as they can help track your pet’s weight. Cat owner’s may need to think about getting a baby scale to do accurate weight measurements at home ($30-50 USD on Amazon). 

What if your pet isn’t losing weight? 

• Decrease the food by 10% 
• Keep checking weight every 2-4 weeks

How fast do we want to see weight loss? 

The goal is a steady 1-2% body weight loss per week. Remember, this is a marathon, not a sprint!

The best chance for success?

Don’t try to go it alone.

Engage your vet and clinic support staff. Schedule those weight check-ins regularly. Let them celebrate your pet’s progress or help you navigate any challenges. Find a friend with an overweight pet and support each other through the journey.

Don’t go it alone!

Weight loss isn’t easy—it can be frustrating and feel impossible at times. It will be a process of rechecking and readjusting, over and over again.

You might feel guilty about restricting your pet’s food and get tired of dealing with their hunger. But the rewards are worth it: your pet will feel better, live more comfortably, and enjoy a longer life.

And you’ll get the satisfaction of knowing you did something hard for them.