Trying to determine the healthiness of a dry kibble pet food by reading the ingredients and nutritional information on the bag is definitely challenging. Even if you're a die-hard label reader when buying food for your family, it won't help you much in analyzing dry pet food. So here are a few key points that will help you grade the quality of a food based on looking at the ingredient list and the guaranteed analysis of a food:
- Look at the protein level, usually called "Crude Protein (min)" in the Guaranteed Analysis. This will give you the quickest snapshot of whether you should even consider the food. Generally, the higher the better – for a dog food you want it to be over 30%, ideally in the mid 30's or higher, and for a cat food you want it to be over 40%, ideally in the mid 40's. If it's below 30% for dogs or 40% for cats, you should pass on it – it is probably not a truly high quality food.
Dogs and cats thrive on animal protein and don't need carbohydrates, and a low protein food will generally have high carbs, usually from a bunch of unhealthy ingredients like grains or grain by-products. If these carbs are not used for energy, they are converted to fat. In the case of cats, they preferentially use protein and fat for energy, so virtually all the carbs in dry food are excess and converted to fat. Dogs' digestion is similar to humans - they can use carbs for energy, but again, any excess is stored as fat.
- Look at the first 5 or so ingredients, which will tell you about where the protein is coming from. Ideally it will be coming from animal-based ingredients like meat, poultry, and fish – and meals made out of them. A meat/poultry/fish meal is a concentrated form of that protein made by rendering, a cooking process that separates the protein from fat and moisture. The way dry kibble is made in an extrusion process, there must be rendered meat, poultry, or fish meals in a high protein recipe; because too much whole deboned meat will have too much moisture for the process to work.
Look for named animal proteins and meals like lamb and lamb meal, chicken and chicken meal, whitefish and whitefish meal, etc., as opposed to generic meat meal, poultry meal, meat and bone meal, etc. – and meals with the word "by-product" in them. These generic meat meals and by-product meals can be made of dead and diseased animals, as well as things like heads, tails, guts, feet - and in general not things you would want your pet to eat (think pink slime). It is okay to have some non-meat proteins in the first 5 ingredients (like peas or eggs), but ideally not in the top 2 or 3, because you want most of the protein to come from meat/poultry/fish.
Look for healthy fats, because fats are an important part of a healthy diet, but they are not all created equal. Chicken fat is fine, but a generic "animal fat" is not. This generic "animal fat" is very commonly used, but it's an aggregated fat from any number of species that get thrown into a vat, so it's bad for allergies and it's one of the ingredients most likely to contain the euthanasia drug pentobarbital—yuck! Some fish oil in the food is good to look for, because that will provide Omega-3 fatty acids, which are great for pet health. A great food will include the Omega-3, Omega-6, EPA, and DHA levels in the Guaranteed Analysis, even though it is not required. In addition to generic animal fat, avoid cheap fats like soybean oil and vegetable oils like sunflower, safflower, or generic "vegetable oil", as they are usually entirely Omega-6 fatty acids with no Omega-3's.
Watch out for empty fillers like corn, wheat, soybean, sorghum, and rice ingredients. In addition to being converted into fat, as mentioned earlier, they are often by-products of human food production rather than whole food ingredients, meaning they probably have little nutritional value. In addition, corn and soybeans are genetically engineered (unless they're organic), and since grains overall are too high in carbs they tend to interfere with insulin and glucose metabolism, and lead to obesity.
The rest of the ingredients may include some beneficial nutrients, but they must be there in sufficient quantity to really make a difference. Some fruits and veggies are good because they provide vitamins, minerals, fiber, and – most importantly – antioxidants, but any that are below or among the long list of vitamins and minerals in the ingredient list are not there in sufficient quantity to be meaningful. Some supplemental ingredients can be a good sign, like flax seed (for fiber and fatty acids), glucosamine & chondroitin (for joint health), chicory root/inulin (prebiotics), probiotics, enzymes, and similar ingredients. Any artificial preservatives or colors are not a good sign, so avoid things like BHA/BHT, ethoxyquin, propyl gallate, propylene glycol, benzoates, nitrates, sulfites, and caramel color.
So keep these rules in mind when evaluating your pet's dry kibble, and it's pretty certain you'll get a good healthy food that will help them thrive.