This one's a real doozy. You've seen it on pet foods everywhere; scientists have worked their magic. Just feed this one bag of pet food for your dog or cat's entire life, and they'll live long and healthy lives.
So this is it? After thousands of years, a few lab techs have come up with the perfect formula for your pet. How do they know? Well, it has all the right percentages of protein, fat, fiber, etc. Well, actually it meets "minimum nutrient requirements" established by a quasi-government regulatory body known as AAFCO. You're reading this right: if a bag of pet food meets "minimum" requirements, then it's complete, no, 100% complete, and balanced.
Ignoring that this notion is void of any common sense, let's examine a few glaring issues here:
First, the aforementioned "minimum nutrient requirements" keep changing! One particularly ugly example of this: in the late '80s, researchers concluded that thousands of cats dying because of taurine deficiencies. Science Diet, Purina Cat Chow, and other famous foods were some of the foods used in the study; turns out cats aren't like other animals that were sampled to determine necessary taurine levels. Did this change the paradigm for pet food manufacturers? Nope! They just added the taurine--we know it wasn't 100% before, but it's 100% complete and balanced now!
Second, these nutrient requirements completely ignore the importance of ingredient quality. The theory goes, and this is seriously taught even in vet schools, that it doesn't matter if you use garbage (actually a legal ingredient for pet food according to AAFCO), leather, etc. so long as it contains the right percentages of protein, fat, etc. This notion is bad enough. But even if it were true, the idea of perfectly complete and balanced percentages is nonsense: to deem a food complete, just by containing a relative few nutrients (there are many more nutrients, both known and unknown, than are included in the requirements), one must assume that everything else nature has to offer (even things we don't yet understand) has no part in any picture of 'completeness'.
Finally, let's examine the protocol for determining whether a food meets these requirements--the vaunted AAFCO feeding trials. The standards to which pet food manufacturers must conform are regulated by the American Association of Feed Control Officials--or AAFCO. You've probably seen AAFCO statements on pet foods you've purchased: stating that they have passed AAFCO feeding trials for “all life stages”, “puppies”, “pregnant/lactating mothers”, etc.
Unfortunately, these standards leave a lot to be desired:
- 8 dogs older than 1 yr. must start the test
- At start all dogs must be normal weight & health.
- A blood test is to be taken from each dog at the start and finish of the test.
- For 6 months, the dogs used must only eat the food being tested.
- The dogs finishing the test must not lose more than 15% of their body weight.
- During the test, none of the dogs used are to die or be removed becasue of nutritional causes.
- 6 of the 8 dogs starting must finish the test.
And that's it. The dog's alive, and it lost only 14% of its body weight--"100% complete and balanced nutrition!"