While the pet treat/pet food industry isn’t regulated the same way our human food is, all pet food labels require a "guaranteed analysis" on the label to advise you of the product’s nutrients content.
Guarantees are required for minimum percentages of crude protein and crude fat, and maximum percentages of crude fibre and moisture. Guarantees for other nutrients are normally voluntary, although additional guarantees may be required to support claims made on the label. For example, claims such as “with calcium” or “high in vitamin E” would require those details.
The best means of determining appropriate guarantees is by laboratory analysis. An analysis of the finished product includes testing for the four nutrient components mentioned above in addition to ash - results are typically reported in percentages as fed. If unsure as to the units reported, it is prudent to ask the laboratory for clarification.
What Do All These Numbers Mean?
Unfortunately, most pet food manufacturers really don’t make it easy on you to figure out what's actually beneficial for your pet to eat. Being committed and savvy is all part of being a great pet parent, and by doing the calculations, you can actually figure out what pet food companies are really adding. Luckily, the math isn’t too tricky.
Protein
Protein provides calories and also the building blocks for virtually every structure in your dog’s body. They build muscles and soft tissue, skin, hair and nails, blood cells, neurotransmitters and the enzymes that control virtually every action in the body. All animals need protein to maintain muscle and bone strength, and puppies require a lot of it to help them grow into their adult-sized bodies. According to PetMD, at least 10% of your pet's daily diet should be protein - typically more is better, because dogs may not be able to digest all of the nutrients in their food.
Fat
Dietary fats are another necessary ingredient to promoting a well balanced diet. Fat also provides energy — and it does much more than just store fat for energy. Fats (or lipids) function as chemical messengers, they form the membranes of all the body’s cells, they help the body absorb fat soluble vitamins (A, D, E and K), and they control hormones and play a huge role in inflammation. According to the National Research Council, an American scientific research unit of the nonprofit National Academies, your pet’s daily diet should contain at least 5.5% fat.
Moisture
A high quality pet treat or pet food will have all the protein, as well as other key ingredients, that your dog needs to stay healthy. A good food for your pet will have a substantial dry matter protein content, typically above 20%. Moisture is the water content of food, as expressed in a percentage. As an example, dry dog kibble tends to have a moisture content of between 6 and 10 percent, semi-moist foods between 15 and 30 percent, and wet foods around 75 percent.
Ash
In dog food, ash is not like it sounds. Contrary to what you may have heard, it’s not a filler intentionally used to dilute a recipe.Ash is what’s left over after any food has been completely incinerated. It’s the final product of food combustion. In other words, if you were to completely incinerate a can of dog food, all three major nutrients (protein, fat and carbohydrates) would burn away, leaving just the food’s minerals behind. Mineral nutrients (like calcium, phosphorous, zinc, iron, etc.) make up ash, the ultimate residue of food combustion, and are found in bones of animals (which is why you’d fine a larger amount of ash in our dried sardines, since they are whole sardines including their edible bones).
Omega 3 & 6 (Essential Fatty Acids)
Essential Fatty Acids benefit almost every cell in our bodies, and they do the same in your dog's body. Both omega-6 and omega-3 fats have the ability to control hormones — and the hormones they control have very different jobs. The omega-6 fatty acids produce hormones that increase inflammation, which is an important part of the immune response. They also help with blood clotting and cell growth. The hormones produced by omega-3 fatty acids also control the immune system and they work alongside the omega-6 fats in an antagonistic manner. Balance between these fatty acids is an important part of a healthy immune system. Both fats are important and your dog needs both in his diet. But these fats must be reasonably balanced for a balanced immune system, and today’s modern diets make this balance difficult.
Calories
Counting calories might be an everyday activity for humans when making lunch choices, and it’s equally important when considering what, and how much, to feed your pet. If your dog is very active, goes for long walks or extended plays at your local park, you want to consider upping the amount of food they have in a day or choosing foods higher in calories. Puppies and kittens require more calories even if they’re not particularly active that day because they’re using most of them for growing their bones, muscles and more. This is why it’s important to understand the amount of calories in a given portion or in a single treat.