How Much Should You Feed Your Pet?
By Stefanie Wong, DVM
Watt Avenue Pet Hospital – Veterinary Sacramento
It’s a great question to ask. Here, I’ll break down the calculations that we make when figuring out how much your pet should be eating.
The first thing you should know how to calculate is what we call the RER, which stands for Resting Energy Requirement. This represents the calories your pet requires to carry out his/her daily body functions like breathing, digesting, thinking.
1. Determine your pet’s weight – feel free to come in to Bishop Ranch Veterinary Center and use our scale so you’re starting with a current weight. Another option is to pick them up and step onto your scale at home then subtract your weight from that number. This is their weight in pounds.
2. Now we need to translate that weight into kilograms (kg). You do this by dividing their weight in pounds by 2.2.
3. We will use a rough formula to get their RER, which is:
- RER = 30 x (body weight in kg) + 70
4. The number you get from this formula is the number of kilocalories (kcal) that they need per day for daily body function.
- For example: Buddy weighs 20 lbs., or (20 divided by 2.2) = 9.1 kg
- His RER = (30 x 9.1) + 70 = 343, which is the number of kcal Buddy needs to eat per day.
5. Look at the bag label on your pet food. You’re looking for ___ kcal/cup. This will allow us to take the final step, and calculate how much you should actually be feeding. As an example, Blue Buffalo Life Protection formula with chicken and brown rice contains 378 kcal/cup.
Going back to Buddy: He can eat 343 kcal/day. If you divide 343/ 378 = 0.9 cups, which means he should be getting under 1 cup/day to meet his resting energy requirement. If you look at Blue buffalo’s label, they actually recommend you feed him anywhere from 1 ¼ – 1 ¾ cups/day. Why the difference?
Dogs that are growing, active or working have higher energy requirements and therefore need more calories. For example, a growing puppy requires 3 x RER (going back to the example with Buddy, if he were a 8 week old puppy, we would actually want to be feeding him 3 x 343 or 1029 kcal/day!). Active, working dogs (for example sled dogs, agility dogs, police dogs) require anywhere from 2-5 x RER. That being said, most average pet dogs only need 1.6 x RER.
Now, let’s say your dog is overweight. In that case, we’re aiming for weight loss. You would want to only feed 1 x RER (using their ideal weight, rather than their actual weight).
Cats, in contrast to dogs, have much lower energy requirements. Neutered or spayed cats should be fed only 1.2 x RER, geriatric (>10 years old) cats only need 1 x RER. Like dogs, if you cat is overweight, we should be targeting 1 x RER (using their ideal weight).
Most pet food feeding charts provide estimates that cover ranges for intact, active animals. Their feeding recommendations are often way higher than what the average pet needs.
Also, keep in mind that treats should be included in your pet’s total daily caloric intake.
The Bottom Line
All pets are individuals. Due to differences that result from breed, activity level and inherent metabolism, these numbers can only give an estimate at best for how much you should be feeding. The amount itself will need to be tailored to your pet and may need to change depending on how their weight fluctuates in response to how much you’re feeding.
How to know you’re on the right track
I use a pet’s Body Condition Score (BCS) to guide my recommendation on whether a pet needs to gain or lose weight. Ideally, you should be able to easily feel (but not see) your pet’s ribs – there should be no fat cushioning in between the skin and the ribs. Your pet should have a waistline, from the side profile and from above.
I would recommend you use this article and calculations we’ve performed as a starting point and then track progress using a diary with monthly-weigh ins. At your next annual visit, your veterinarian can help to determine your pet’s body condition score and let you know what their ideal weight should be. It will take some work, but it’s worth it. By getting your pet to an ideal weight, you are giving them the best chance for a healthy, happy long life.
Talk to Sacramento Veterinarian Sue Barrett if you have questions about how much you should be feeding your pet!