A recent New York Times article on high fructose corn syrup ("A Sweetener With a Bad Rap"), noted:

"The Food and Drug Administration never established rules on what, exactly, 'natural' means, allowing companies to pitch products as natural even if they contain high-fructose corn syrup."

However, back in the 1920s, a furious debate was underway regarding the labeling/naming of "adulterated" products. Back then, high fructose corn syrup did not yet exist. However, "corn sugar" and "corn syrup" were entering heavy production. The corn industry wanted to label the product "corn sugar" or "corn syrup", instead of "dextrose", as the law then required. For those attempting to enforce the label laws, the concern was:

low-cost of corn sugar production -> over supply of refined sugar -> increased consumption -> negative effect on public health

Here are two quotes on the subject:

from Dr. Harvey J. Wiley, taken from the hearings on Interstate and Foreign Commerce on H. R. No. 39:

"Now if we flood our stomachs with dextrose, then we will need half a dozen artificial pancreases to take care of it, and there is the real danger, the threatening danger, as every wise physiologist will tell you, from that source. So that both by reason of paralysis of our digestive apparatus through lack of functioning that is a threat in itself, and by reason of the increase of the amount of dextrose which we ingest far above what we need we endanger our health in the most serious way. So that I voice now, and with all the emphasis I can put on it, my disagreement with every other person, except Dr. Menges, who has testified here, and it has been unanimous almost, who has said that this predigested and prechewed dextrose is harmless. I deny it and I think I have most scientific grounds to convince you, gentlemen, that it is not a harmless substance."

Quote 2: "the eminent physician", Dr. E. L. Fiske, from testimony given on Jan. 21, 1927:

"I concur in your views that it is unwise to make any change in the present law requiring that dextrose should be so labeled. While it is quite true that dextrose is just as available a fuel as sucrose, indeed more available because of the fact that the action of digestive enzymes is not required, I feel that the present consumption of sugar is far beyond the physiological needs of the population and tends to narrow the diet. I believe that food sugars should be drawn from natural sugars, such as fruit sugars and sucrose. Statistics would indicate that diabetes is increasing in this country and I can see some point in your caution that the use of a predigested sugar may in itself not be in the interest of public health. In regard to no other food is predigestion looked upon as a physiological advantage, but rather the contrary, except in the emergencies of illness."

After thousands of pages of Congressional testimony and a change in the federal administration, the corn lobby eventually won out. However, the concerns of Dr. Wiley and others have also come to fruition. In her 2006 book, What to Eat, Dr. Marion Nestle notes that 142 pounds of sugars are now available to every American. In an informal survey of a supermaket, she estimated 25% of aisle space (2,005 linear feet) was used for "sugary foods."

Source of 1920s quotes:

The History Of A Crime Against The Food Law: The Amazing Story Of The National Food And Drugs Law Intended To Protect The Health Of The People Perverted To Protect Adulteration Of Foods And Drugs
- By Harvey W. Wiley, M.D.
- Copyright, 1929, by HARVEY W. WILEY, M.D. Washington, D. C.

Note: the author, Dr. Harvey W. Wiley, is pictured on the FDA history page. He is credited for creating the "predecessor" organization to the FDA as well as pushing through the 1906 Food and Drugs Act which "forbade interstate and foreign commerce in adulterated and misbranded food and drugs." His book, "The History of a Crime Against the Food Law", details the politics which took the teeth out of the law.