For years now, I have been saying that "nutritional science" needs to have it's basic methodology changed in significant ways.  Specifically, it is a discipline based upon abstract categorizations, such as calling lard, which is about 40% saturated fatty acids, a "saturated fat."  Basic logic dictates that calling lard a "half saturated fat" would be an exaggeration; calling it a "saturated fat" is simply ludicrous.  Some "experts," realizing this, have used phrases like "animal fats," but this is contradicted by the evidence, and some animals fats can have very different compositions than others.  Other "experts" are using phrases like "red meats" and "processed meats," realizing that highly saturated fat sources, like coconut oil, are clearly not at all dangerous, and in fact appear to have significant health preserving qualities.

 

Recently, a scandal involving pet food in the USA has led to an investigation into what caused the pet deaths, and it appears that the problem has been determined:

 

QUOTE:  Scientists at the University of Guelph have made a chemical discovery that may explain how pets in the United States and Canada were affected by chemical contaminants discovered in recently recalled pet food products.  Perry Martos and colleagues in the Agriculture and Food Laboratory at Guelph’s Laboratory Services have found that melamine and cyanuric acid can react with one another to form crystals that may impair kidney function...  “This is a significant finding,�?said John Melichercik, director of Analytical Services in Lab Services. “We knew these two compounds had been implicated, but because neither seemed sufficiently toxic on its own, it was unclear how they might have been involved.�?nbsp; UNQUOTE.

 

SOURCE:  http://www.sciencedaily.com/releases/2007/05/070501105514.htm

 

I cite this passage because it is an example of one way to do nutritional science that deserves to be called science, as it is founded upon basic chemistry.  Another way one could pursue nutritional understanding is by studying the effects of specific diets, rather than categorizing foods and then ignoring all kinds of potentially causative factors, such as food is processed and cooked.  Thus, one would have to control for things like pasteurization and homogenization, for instance, if one wanted to make a claim about "milk products."  Of course, there are several other factors involved, such as how the item is cooked, if it is cooked.  It would not be difficult to determine which specific diets appeared to be healthiest, but a problem is that once this was determined, there would be little for "nutritional scientists" to do.  Chemists and biochemists would still have work to do (as the passage cited above demonstrates), but this approach could put "nutritional scientists" "out of business."  Like many have said in a similar context, if a cure for cancer was found, a lot of people would have to find something else to do with their lives.