Pet food nutritional facts are lying to you (Explanation in the body)
Hello! I realize the title sounds a bit clickbaity, but it's not hyperbole.
The short explanation is the nutritional facts on pet food includes its water weight, which makes the other percents like protein and fat on the packaging effectively pointless and impossible to compare from one product to the next, and they almost never include the ash and carbohydrate content. What you need is the dry matter basis, which is the percent breakdown excluding the water.
So what to do?
Well if you want a simple answer, just use https://catfooddb.com/ which has already done most of the leg work for you. Go find your preferred brand and check out the foods you're already feeding and pay attention to the pie charts to see how much protein, fat, and carbohydrates there are in the food you're currently using.
Is your food not listed? Don't fret!
If you are taking your pet food choices seriously, you can repeat her findings (often more accurately due to finding newer and more accurate data) on