It would seem to me that, by now, scientists would be able to trace the progress of something like trans-fats (just as an example) through the digestive process and follow its entry into the bloodstream determining its ultimate effects on the body.
Instead, it appears, we are subject to a never-ending parade of "studies" which can only -- at best -- find a correlation between the ingestion of a food and the relative health of the population in the study. It's not so much science as statistics.
I don't know. Maybe all the really good scientists have been bought off to study global warming.
When people do Atkins, HCG, or Paleo diets the weight comes right off. It's pretty clear that the government food pyramid and its ridiculous overweighting of grains is the main culprit.