Have you ever scanned the ingredients in a commercial dog food and thought, "How can this be healthy?" Some may think most pet foods available in stores today are so highly processed and full of preservatives, they aren't any better for our dogs than potato chips are for humans. However, unlike potato chips, a pet food must prove it can provide all the nutrients needed by the dog, cat, puppy or kitten before it is sold. So before your dog takes another bite, read these tips on how to find the healthiest food for your pooch.

[edit] Steps

Understand that arguably, the best ratios for a healthy dog's diet are about 40% meat, 50% veggies, and only about 10% grain or other carbohydrate. Choose pet food close to this ingredient ratio. However, this type of information is not available from the regulated part of the label (ie, guaranteed analysis or ingredient list).
Ensure that meat protein sources are high in the ingredient list. You could look for three of the first five ingredients listed on the label as a form of protein such as chicken, lamb, venison. Although by-products can include chicken beaks, feet, bones, etc., reputable manufacturers will select ingredients processed to remove such indigestible material. Rarely, you may need to look for foods that exclude corn, cornmeal, and wheat, due to concerns about potential allergens. Grains can be a long-term source of energy and energy storage for dogs, but they can also be used as a cheap filler in order to boost the food's protein percentage. Watch out! Any grain you feed your dog should be used in whole form so that it supplies more fiber, vitamins and minerals. The best grains for dogs (when used in the proper percentages) are rolled oats, barley, quinoa, millet, and brown rice.
Often, low quality dog foods will list a meat ingredient first, which will be followed by several by-products and fillers. In this case, although meat is listed first, there are actually MORE fillers, which changes the ratio noted above.
A well-planned vegetarian diet can work for dogs, although dogs are carnivores by nature. Dogs need animal protein. Would a dog naturally be vegetarian? No. Most veterinarians and holistic practitioners agree that although a dog can survive on a vegetarian diet, they may not thrive on it.
Be aware that while preservatives may be necessary to keep the food edible, preservatives do not have to be artificial chemicals that might be cancer-causing agents. Avoid pet foods that use chemical preservatives BHA, BHT and Ethoxyquin. Vitamin E & vitamin C are great preservatives that are much better for your dog.
Choose Premium Brand dog foods instead of Economy Brand dog foods. The cheapest ingredients are rarely the healthiest ones.
Go holistic. Holistic foods are 100% natural and 100% nutritious. They contain human-grade ingredients. One holistic pet food manufacturer provides an free online video "The Truth About Pet Food" you can watch here.
Some may consider this rule of thumb: If you wouldn't eat it, your dog probably shouldn't eat it either. (Think animal fat and added salt or sugar.) But there are some things you would eat (such as chocolate, grapes, raisins, white flour and onions) that are NOT good for your dog. Don't make the mistake of thinking all human food is appropriate for your canine. Canine and human nutritional needs and likes differ, such that what is appropriate and appealing for your dog may not be something you care to eat. In addition, some ingredients considered undesirable by US consumers (eg, by-products) are enjoyed by humans in other cultures.

[edit] Tips

If you really want to know what's in your dog's food, try making your own dog food. It's not as hard as it sounds! There are plenty of recipes and meal plans available online, but beware. Really research what you're doing. Consult with your veterinarian to make sure the diet is well-balanced. A very helpful book is "The Whole Pet Diet" by Andi Brown, and she gives some good recipes. If you'd rather save time and pay more for the same thing, she also produces Halo Spot's Stew, which is her homemade recipe canned.
Every dog, like every human, has different nutritional requirements. It is very important you check with your veterinarian to determine what foods best meet your pet's needs.
A good way to see if your dog's diet is suitable is to check how it comes out the other end. No, you don't have to get too close to it, but as you pick it up in your poop scoop or baggie, check it for consistency and general appearance. A healthy dog's output should be firm and without any traces of blood or mucus.
When changing your dog’s food it is important to switch gradually, as it is easier on the dogs digestive system, and reactions to the new food will generally be less severe. It is recommended that you gradually increase the amount of new food in the following sequence: 1/7, 1/3, 1/1, 3/1, 7/1, and 1; this being the portion of new food to old food (first change: a total of 8 cups of food [that would be one big dog!] with one cup of new food with 7 cups of old food). Each change should be gradual with several days (5 days to a week is best) between changes. All in all it should take a month or more. Even a 4-day transition can help avoid digestive upsets.
Sometimes you can't afford the very best for your pets, so it comes down to trying to find the best that fits your budget. Use what you've learned about ingredient labels to make the best decision.
Often, you'll find what seems to be a good dog food in almost every aspect, but it has too much grain. To help balance the ratios, try a grain-free canned dog food to supplement your dry food with. Dogs love canned food mixed with their food.