Meow Mix ranks about the same as Friskies... Corn, lots of grains, by-products...
In general, just about any food that you can find in the grocery store is not very good quality, especially the kinds that come in fancy colored shapes...
This might be a long post, so bare with me... 8)
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Here's an example of the first 10 ingredients in a bag of Friskies:
Ground yellow corn, corn gluten meal, chicken by-product meal, meat and bone meal, beef tallow preserved with mixed-tocopherols (form of Vitamin E), soybean meal, corn germ meal, salmon meal, tuna meal, brewers dried yeast.
Notice how corn is the first 2 ingredients (ingredients are always listed in order with the ingredients with the highest percentage first). Corn is basicly just a cheap filler and cheap protien source, and it is also a common cause of food allergies.
Chicken By-products is an animal protien source, but is generally undesirable in a good pet food. In the wild, cats naturally eat some by-products, but not a very large percentage. The AAFCO defines chicken by-products as: "clean parts of the carcass of slaughtered chicken, such as necks, feet, undeveloped eggs and intestines, exclusive of feathers, except in such amounts as might occur unavoidable in good processing practice"
The problem that many people see with by-products is that its hard to say exactly whats included.
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A better food will list a named meat (i.e. chicken, turkey, lamb...) as the first ingredient. The importance of having a named meat (as opposed to "poultry" or "meat") is that we know what animal it actually came from.
Here is an example of the first 10 ingredients in a bag of Purina One:
Chicken, brewers rice, corn gluten meal, poultry by-product meal, wheat flour, animal fat preserved with mixed-tocopherols (form of Vitamin E), wheat gluten, whole grain corn, non-fat yogurt, fish meal, brewers dried yeast
The first ingredient is chicken, which is a good start, but you'll notice that it still contains several grains in the top ingredients, specifically corn. It also contains poultry by-products (and "poultry" is an obscure term).
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And here's an example from a bag of Wellness Cat food, which is one of the top premium brands:
Deboned Chicken, Chicken Liver, Turkey, Chicken Broth, Sweet Potatoes, Carrots, Vegetable Gums, Flaxseed, Potassium Chloride, Alfalfa, Cranberries, Blueberries....
The first several ingredients are named meat sources. Wellness is also a grain free food (although not all premium brands are), so you won't find any corn, rice, soybeans, etc on the list. The vegetables and fruits are used as natural sources of some vitamins and minerals...
There's still a lot more to it than that, but I hope that gives you a start on knowing what to look for when choosing a cat food...
If you're on a budget, I'd suggest trying Nutro or the Chicken Soup (for the Pet Lovers Soul) brand. Its not as good as the top premium brands, but it is significantly better than the grocery store brands.
Here's a link that will also be helpful in making decisions about what your cats should eat:
FEEDING YOUR CAT: KNOW THE BASICS OF FELINE NUTRITION