I received this question from Steve, who needed to understand how calories are calculated in cat food:
I’ve been meaning to call your show, but I just can’t seem to find the time. I want to thank you for responding the first time and printing my question in your blog.
There’s one other question that’s come up regarding Weruva. I’ve been reading Cat Forum and there’s some concern about the low caloric count of Weruva (84 calories per can) and the low fat percentage. My cat has been eating almost two 5.5. oz cans per day but her weight stays constant at around 8 pounds. Lulu’s a dainty thing and may be a Turkish Van mix so this could be around her ideal weight, but the vet would like to see her gain at least a pound.
As I previously wrote, Lulu had skin allergies and would scratch and lick her face and legs until they were bald and had wounds. Since I switched to Weruva, the skin problems have cleared up but I would like to add a higher calorie food to her diet which is higher in fiber. I’m just afraid that another food will cause her skin allergy to flare up again.
And here’s the answer from David Forman, who owns Weruva. It’s a really long answer (David is so dedicated and thorough in educating and reassuring his customers):
Weruva’s calorie content reading is lower than most brands. There are two primary reasons for this with respect to the ingredients used. Also, our caloric count is based on the metabolizable energy as well as the caloric content as it pertains to the guaranteed analysis.
Regarding the food, we add little to no carbohydrates to our formulas, so there are minimal calories coming from carbohydrates. Grain Free does not mean carbohydrate free, and as cats are obligate carnivores, it is important not just to focus on low or no grains, but to focus on overall low carbohydrate content. In addition, all of our meat cuts are very lean, such as the skinless chicken breast, so the fat content is also low. A gram of fat has 9 calories and a gram of protein has 4 calories. Therefore, foods with higher fat content and higher carbohydrate content boost up the caloric count. There is no shortage of calories coming from high quality protein.
As you likely have noticed on pet food labels, there is a guaranteed analysis expressed in minimums and maximums. These are required for labeling, and the minimums and maximums are put in place more or less because pet food processing, in large part, relies on the availability of raw materials that remain after human food processing. Because of inconsistencies in raw material sourcing/availability, the pet food industry implemented the range of minimums and maximums and does not require actual listings.
How does this all relate to calories? If raw material sourcing accounts for inconsistencies, it follows that caloric count cannot be entirely consistent. I cannot speak for other brands, but I have heard that some manufacturers take the average of a few production runs to come up with caloric count. We use the same cuts of meat and carefully weigh the amounts of food going into each can, so we can be pretty consistent with our calorie count. However, along the lines as to the way pet foods are required to be labeled, we calculate our calories in large part based upon the guaranteed analysis. For instance, if we guarantee 10% protein in a 156g can of food, that is 15.6g of protein. As a gram of protein has 4 calories, there are 62.4 guaranteed calories coming from protein. In a similar calculation, there would be 21.06 calories coming from fat if we guaranteed 1.5% fat (min). Same for carbs. In reality, the actual readings of protein and fat will be higher in our cans, as we account for possible underfills in the production runs.
In addition, our calorie content is the metabolizable energy (ME) of the food, not the gross kcal. ME is essentially the energy that is left over after the digestion and processing of the meal.
The question you asked is a good one, and there really is no correct caloric amount. The great news is, you are feeding all canned. Unlike dogs, cats that are eating the right foods will more or less know when it is time to stop eating. In that regard, as long as the obligate carnivore kitty is eating high quality protein (such as animal based meaty cuts), he or she will generally not overeat.
With that said, the caloric count of Weruva, as you have seen, may appear to read lower than that of other brand. We recently received a similar inquiry to yours, and this is the response we gave:
The important thing to note about cats, dogs and even people and calories is that not all calories are created equally, and both pets and people will fare differently on different foods with the same caloric count . . . so looking at calories alone does not always get you there.
For instance, the correct and appropriate food for “obligate carnivore” cats is meat . . . meat being comprised of protein and fat. Cats run quite efficiently when eating a high quality meat based diet and will require less caloric intake than cats not eating similar quality foods. In contrast, cats that eat kibble, which contains high concentrations of carbohydrates (even the grain free ones) and cats eating diets that use plant based proteins as opposed to meat based proteins will not be eating foods that nature intended for cats. For that reason, cats may require higher caloric consumption to get their nutrition.
Unlike dogs, as long as cats are eating meat based diets, they more than likely will not overeat and they more than likely will not gain weight. In that regard, we do not urge a focus on actual caloric count. Instead, we says as long as they are eating the right foods, let them eat as much as they want. Our philosophy is similar to what it recommended by Tracie Hotchner, author of The Cat Bible and Host of Cat Chat® on Martha Stewart Living Radio. Feed cats twice a day (sometimes once, sometimes more) and let them eat as much high quality canned food as they want in a 15-20 minute period.
