Seems it is coming out that most/all of us agree that giving some type of feeding trial seems to be the best way to evaluate the quality of a particular feed. None of us are looking for the guaranteed, highest quality feed, regardless of price... just the one that seems to work best for our animals. This works for all animals, from kittens to goats to swine, or cattle, with only a few eccentric exceptions.
All animals are just "conversion machines", meaning they take whatever food they eat, do a preliminary intestinal breakdown and absorb whatever is possible. Once inside the body (within the 'gut' from stem to stern is considered to still be outside the body) it is further deconstructed (metabolized) into it's components. The body then takes what it needs to meet it's requirements, whether it's for growth, tissue repair, fighting disease, or just energy to accomplish all it's tasks, including moving and staying warm (and cool... takes energy, too). Most animals also construct some of the materials they need that are not supplied in their diets, like some amino acids used in building certain proteins.
Energy is the greatest demand a body has to meet daily. Excess energy is converted into fatty products (triglycerides and fatty acids) that are further 'converted' and stashed away as body fat (adipose tissue) to be used... whenever. All of what is left, both in the intestines, and what has not been metabolized, has to be excreted, either directly, or again converted into something else in the kidneys or liver and passed on out.
Some feeds are obviously better than others, but it is neither fair nor accurate to describe any feed as 'junk', or any of the feedstuffs going into it's manufacture as toxic or other misleading terms. Animal foods are strictly regulated, and must meet standards of manufacture and nutritional value. Failures to do this do result in recalls. Anything truly toxic is not allowed, and melamine is the latest I can recall... from China? Intentionally introduced as a supplement. If anyone believes something is truly toxic or otherwise 'bad', it should be reported. A low quality (nutritionally) item will create no alarm, however.
Use of derogatory terms to describe most of the foods currently on the grocery store shelves is uncalled for and inaccurate. Most of our OP's get their foods off those shelves and it does no one a service to disparage their choices. Make a suggestion, not an evaluation. One's own personal experiences are just that... personal. True malnutrition, other than an inadequate amount of food being given, is seldom seen in practice, and usually is associated with 'home cooked' foods using formulas sometimes concocted out of 'logic and "common sense" '. There are many examples passing through clinics of food 'inadequacies' that result in skin and coat conditions, or reproductive problems that are not acceptable to owners (as example, but not limited to.) This may be either the fault of the feed, or the particular animal, or breed.
The Public's pet world is replete with inaccurate or inadequate information regarding nutrition. Where we can, let's try not to contribute to it. End of minor rant (and TMI?)
