How to Calculate the Calorie Content of Cat Food
- Rachel
- Sep 11
- 5 min read
Updated: Sep 23
In this article:
No one enjoys counting calories, and when it comes to our pets, we have the additional problem of not knowing what or how much they should be consuming. Some cat foods will give you the calorie content per cup, kilogram, 100g - or per can/sachet of wet food - but more often than not, we're left guessing.
This doesn't pose much of an issue, since most owners don't know how many calories their cat should be eating. Most of us abide by the feeding instructions of any particular food, which are usually based on the weight or life stage of cats. However, it doesn't take into account other factors such as body condition, health status and lifestyle.
For example, if your cat is obese and you're feeding it based on its current weight, then it'll continue being obese until you reduce its portion sizes. Likewise, a sedentary indoor cat won't require as many calories to burn off as an active outdoor cat. This lack of understanding leads to many domestic cats being overweight and developing associated health conditions.
Related post: 5 Indoor Cat Foods Rated: Are They Really Worth it?
Food manufacturers are partially to blame, with a lack of transparency regarding the ingredients going into food. In my previous post, I broke down the formula for calculating carbohydrates with a step-by-step example, as this information isn't included on a cat food label.
As quoted on the FEDIAF website:
"There exists no minimum level of carbohydrates which needs to be in pet food, but carbohydrates provide a concentrated source of dietary energy and dietary fibre."
What this really means is that grains and vegetables are used to bulk out food as a cheaper source of protein. Since it's not listed as an independent nutrient value, we have no way of knowing how much protein comes from animals and how much comes from plants.
This isn't an issue with dogs, who've evolved to survive on a combination of both; however, cats are - and always have been - obligate carnivores. With some foods containing as little as 4% meat, it's crucial that we as owners take a closer look at what we're feeding our cats to prevent and avoid long-term health conditions.
Research into the effects of carbohydrates in a cat's diet has mixed results, which you can learn more about here: Cats and Carbohydrates: Is Dry Cat Food Bad for Cats?
How to Calculate Calories in Cat Food
Work out the carbohydrate content
While carbs aren't important for a cat's survival, we still need to know how many are in our cat's food in order to calculate the calories. We can do this using a simple formula.
Find the analytical constituents section on your cat food label and add up the percentages of protein, fat, fibre, ash and moisture.
Example:
Protein 27% + Fat 16% + Fibre 2.5% + Ash 7% + Moisture 8% = 60.5%
Subtract the total from 100:
100 - 60.5 = 39.5
This means the carbohydrate content per 100g of the example cat food is 39.5%
If the percentage of moisture isn't listed then you can assume it's between 8-10%.
For more tips and advice, including how to calculate nutrients on a dry matter basis, refer to this dedicated post: How to Calculate Carbohydrates in Cat Food and Understanding Dry Matter Basis
Work out calories per gram
Before we can work out the total amount of calories in cat food, we have to know how many calories are coming from protein, fat and carbohydrates.
Each gram provides the following unit of energy:
1 gram of protein = 3.5 calories
1 gram of fat = 8.5 calories
1 gram of carbohydrates = 3.5 calories
We know from the example in step one that the protein level is 27%, the fat level is 16% and carbohydrates are 39.5%. This means that in 100g of cat food, there are 27 grams of protein, 16 grams of fat and 39.5 grams of carbohydrates.
To get the total amount of calories from these figures, we have to multiply them by the number of calories that each gram provides.
Example:
Protein:
1 gram of protein provides 3.5 calories. Since there are 27 grams of protein in this cat food, we multiply that number by 3.5 so it looks like this:
27 (grams) x 3.5 (calories) = 94.5
This means that 94.5 calories come from protein.
Fat
1 gram of fat provides 8.5 calories.
16 (grams) x 8.5 (calories) = 136
136 calories come from fat.
Carbohydrates
1 gram of carbohydrates provides 3.5 calories.
39.5 (grams) x 3.5 (calories) = 138.25
138.25 calories come from carbohydrates.
Add up total calories
To find out the total calorie content, all that's left to do is add up the numbers above.
94.5 calories (protein) + 136 calories (fat) + 138.25 calories (carbohydrates) = 368.75
Therefore, this example cat food contains 368.75 calories per 100g.
How Many Calories Does My Cat Need?
Now that you have a better understanding of what's going into your cat, you can go beyond generic feeding instructions and adapt the portion sizes according to your individual cat's requirements.
You can find everything you need to know in this dedicated post: How Many Calories Does My Cat Need?
If you need a little more help or prefer a quicker solution, I've linked some cat calorie calculators below that are free and simple to use. You'll need information such as your cat's age, sex, weight, activity levels and reproductive status, and the results will show your cat's total energy requirements.
Online calculators may not be 100% accurate because all cats are different, much like humans, but it'll give you a better idea of how much to feed your cat. You should always consult with a vet if you're unsure, especially if the goal is weight loss/gain. It's important to monitor you cat's weight and overall health, ideally on a weekly basis to ensure they're getting sufficient calories.
Use one of these calculators to get your cat's total maintenance energy requirements (MER):
You don't have to be an expert in feline nutrition to control what and how much your cats are eating. Many opt for commercial food over fresh or homemade because it's easier to understand, only it's not so easy when a lot of information and ingredients are hidden from us. Even commercial food needs a little tweaking to prevent issues like obesity, and I hope this article provides a step in the right direction!
Have you started counting your cat's calories? I know it can be challenging at first, so feel free to leave a comment if you need any hints or tips.
Comments